Chapter X: QUALITY INSPECTION.--In my paper in these pages, in 1894, I (2)

Naturally, the people in small communities feel somewhat more at ease in the matter since they know their milk producer and can hold him responsible. But it is questionable whether the milk supply of the large city is not more reliable. The milk supply in the city is handled by organizations, and these, on the whole, are rather more likely to exercise care in the treatment of the milk than are the small dealers. The advantage of handling the matter through companies is well shown in many European cities. In the large cities of England and the continent the milk business is commonly handled by concerns that distribute great quantities daily. Now, many of these companies deal with the subject in a very intelligent manner. They exercise a very considerable control over the individual dairy farms. Some of them keep inspectors traveling constantly among the farms, spending $10,000 to $15,000 yearly in such inspections. They will receive no milk from a farm until after an inspector has visited it and looked into the hygienic conditions of the dairy, even sometimes going so far as to make an analysis of the water used in the dairy. Only after such inspection has been declared favorable is the milk received in the city. These inspections are repeated monthly. The appearance of a contagious disease on the farm is noted at once and the milk no longer received, although still paid for. These companies employ chemists and bacteriologists to study the character of the milk received. They educate their men into their business, and consequently employ more intelligent help than small concerns can. They can furnish a more uniform product than can be expected of smaller dealers. They soon acquire a reputation for their milk, which they are very careful to preserve. Such firms can exercise a much more satisfactory control over the individual farmer than can even public statute, since, with their systems of inspection, it is possible to have an accurate knowledge of the actual conditions under which the milk is produced. It is plainly within the power of firms dealing in large quantities to control the character of its milk more accurately than can small dealers.

Results, too, appear on the whole in favor of the large dealers. In the cities where there is a system of rigid milk inspection it is comparatively seldom that the milk furnished by such companies is found below the standard. This milk is kept up to the standard, and the companies having a chemical laboratory and having milk from many sources can keep the quality of the milk much more uniform than can a dealer whose supply comes from a single farm. The milk inspectors usually find that it is the small dealers that fail to meet the standard. Moreover, it is a fact that where epidemics have been traced to milk it has always been in communities where individual milkmen bring in milk from one or two dairies and distribute it personally. All the epidemics of typhoid that have been definitely traced to milk have been in small communities, and none traced to the milk of large dealers. It is true that it would be difficult or impossible to trace to the milk a typhoid epidemic which might occur in a large city. No one is likely to receive the milk from the same source for two days in succession, and the mixing which the milk receives in the receiving station entirely obliterates the individual source. If there should be some milk brought to the city which contained typhoid bacteria it would be impossible to determine the fact, for such milk, after mixing, would be thoroughly scattered beyond any possibility of following it. We may, then, question somewhat the significance of the fact, but it certainly is true that while serious epidemics have been caused by milk in smaller cities no such instance has occurred in the large cities, or been traced to the milk furnished by companies that handle it in considerable amounts. It would seem that if milk has ever been the cause of such diseases in large cities there ought to have been some evidence of the fact obtained.

It is probable, therefore, that the small community can hardly feel itself any better off in regard to the milk supply than the larger city. It is, of course, easier to trace responsibility for bad milk if we know where it comes from, but it is less likely to be very bad if it comes from a large number of sources and is thoroughly mixed. The milk in the large city is perhaps forty-eight hours old when it is received by the consumer. But it has been kept on ice, has perhaps been filtered, and many of its bacteria may have been killed by the long-continued cold temperature. So far as concerns the bacteria question, our milk which is thus two days old, appears to be actually superior to milk delivered in European cities, which is only a few hours old. The free use of ice in our milk car produces a more favorable result than the more rapid handling which the milk receives in Europe. The milk company controlling a large territory, with great resources at its command, can put into practice rules which even public statute can not enforce, and which the individual farmer will rarely do by himself. One who is acquainted with the methods of handling milk in our cities finds that the companies are each year improving their methods, and that the milk is in most places becoming more reliable. The proper solution of the milk supply for our communities is in the formation of large companies, provided they are managed partly for the benefit of the public and not wholly for money-making.

There is little question that the public has become somewhat suspicious of milk, and that many hesitate to drink it as freely as in earlier years. This suspicion is more pronounced in Europe than in the United States. Upon the continent of Europe the amount of milk which is used raw is really very small, and apparently its use in this condition is destined to cease. The younger generation of physicians are now being taught that raw milk is a dangerous food, and in some countries even the children in the schools are being taught that it is not safe to drink raw milk. Such teaching can have only one result, and that is the reduction in the amount of milk consumed. Much less milk is used in Europe than in this country. It is used for tea or coffee or for cooking, and of course for infant feeding, but for any one to drink milk as we do in this country is certainly a rarity. The suspicion under which milk has been placed has decreased its use.

The dangers which are feared in milk are of course connected with the distribution of disease. Most persons who thus hesitate to use milk have simply a vague fear, without knowing just what is to be feared. When we put together all the facts in our possession we find that there is good reason for believing that milk is sometimes concerned in the distribution of the following well-known diseases and some obscure ones: The first is _tuberculosis_, which is a disease attacking the cow, and, if located in the mammary gland, may infect the milk with tubercle bacilli, and may subsequently produce the disease in the person who drinks the milk. It should be stated, however, that there is good reason for believing that the danger from this source has been overrated. Second, we have _diphtheria_, which apparently may also attack the cow. The diphtheria germs may get into the milk from the cow, and they certainly do get into the milk occasionally from secondary sources. _Scarlet fever_ apparently is distributed by milk, though whether this disease may come from the cow or only by secondary contamination of the milk is not yet positively settled. _Typhoid fever_ has in a large number of cases been traced to the milk supply. This disease, however, does not occur in the cow, and the germs always get into the milk from a secondary source, such as water or contact with a person who has the disease. _Cholera_ may be distributed by milk, but this is of course of little importance. Of these disease bacteria, the tubercle bacillus probably never grows in milk, while the typhoid and diphtheria germs do. The most common of all troubles attributed to milk are those somewhat obscure _intestinal diseases_ which attack people especially in the summer months, and are particularly common among children. Prominent among these stands _cholera infantum_. These latter troubles, according to our present knowledge, are not produced by distinct species of bacteria finding entrance into the body and growing there, as are the other diseases mentioned. They appear to be produced by bacterial poisons which are in the milk. The bacteria--probably several different varieties--grow in the milk and there give rise to certain poisonous products, and these, when taken into the stomach, produce the diarrhoeal diseases referred to.

The question of more importance is, however, as to the extent of the danger from such causes. This question is much like the famous one of how large is a piece of chalk. There is danger in everything, even in drinking water and breathing air. Is the danger from milk so great as to suggest that we should give up our habit of drinking milk as they have largely done in Europe, or is this danger so slight that we can well afford to neglect it? We can not avoid all sources of disease even if we would. To do this we should need to shut ourselves up in a box, breathe nothing but sterilized air, drink nothing but sterilized water, and come in contact with no other person, to say nothing of wearing sterilized clothes. Such a method will produce physical weakness rather than vigor. We have learned in the last few years that the proper way of avoiding disease is rather by preparing ourselves to resist it rather than try to avoid all contact with possible disease germs. The question is significant, then, whether the danger from milk is so great that we should use every means of avoiding it; or is it one of the slight dangers which we may best class with the everyday incidents against which our proper guard should be simply vigorous health?

It is impossible to say how great is the liability of contracting disease from milk. Sometimes the subject looms up before us in gigantic proportions. When our papers are describing the occurrence of hundreds of cases of typhoid fever in a city, all traced to a milk supply, the seriousness of the problem is very apparent, and very likely we stop drinking milk for a season. But when, on the other hand, we remember the millions of people that are drinking milk daily without injury, and remember that our forefathers have done the same, we grow graver and begin again our old custom. No one can, indeed, pretend to say how great the danger is. That it is greater than that from drinking water is pretty clear. That it is less than that of riding in the cars is probably equally true. That it is greater in a small community than a large one seems probable, and that there is a greater likelihood of its being serious where the milk comes from a single source than where it passes through the hands of a milk-supply company appears to the author to be quite sure.

In his relation to this problem each person must decide for himself. We do not cease to ride in the cars because there is danger here, nor do the innumerable accidents from bicycling deter us from this pleasure. Ought we to give up milk because of an occasional instance of disease? It might be possible to give advice to use milk freely, looking upon the danger as a slight one and one of the unavoidable dangers of living, but if such advice is given some one will instantly declare it bad advice. It might be possible to advise boiling all milk before drinking, and again some authority would say that this is unnecessary and bad. Personally, the author, though living in a small community, uses raw milk with perfect freedom, but would regard it as unwise to allow young children, especially infants, to use it in this way.

As already stated, the agitation over the milk supply is greater in Europe than in this country. While in England milk is used much as in this country, on the continent really little milk is drunk raw, and there is a growing demand for some means which shall deprive milk of the suspicions attached to it. This demand has been rapidly growing in recent years, and has resulted in the appearance of two new industries. These are the preparation of _sterilized_ and _Pasteurized_ milk. Neither of these industries has as yet developed much in the United States, although in our larger cities beginnings are being made along similar lines.

_Sterilized_ milk has been used for many years. Long ago our doctors learned to recommend, for invalids, that milk should be boiled before drinking. This was done before the matter of its relation to bacteria was understood, and when physicians simply conceived that the boiling rendered the milk more digestible. From being used by invalids it came to be suggested in feeding infants, and then, after the relation of milk to possible disease germs had been understood, the general sterilization of milk was widely recommended. The process of sterilization of milk has not taken much of a hold upon the people of this country as yet, nor has it in England. In continental Europe, especially in northern countries, where the amount of tuberculosis is very large, it has made rapid headway, and now in most of the cities sterilized milk can be bought on the streets just as easily as ordinary milk.

In sterilizing milk as it is done in Europe the destruction of the disease germs is not the only purpose. An object of perhaps equal weight is to produce a milk that will keep. There are many circumstances where it is desirable to carry milk for long distances, and to lay in a supply to last many days or even weeks. Under these circumstances sterilization is resorted to, since it preserves the milk.

There are various methods of sterilizing milk. The simplest, and doubtless the most common, is simply the boiling of the milk. This can easily be done by any one at home, and is, beyond question, very widely resorted to. But where the sterilization is to be performed by a public-supply company, boiling is not satisfactory, since the milk, although it will keep some time, is not indefinitely preserved. The common method used is heating with superheated steam. The milk is placed in bottles of special device, holding about a pint or a quart, and are placed, hundreds at a time, in a large chamber which can be hermetically sealed and then filled with steam under pressure. Here the temperature rises to 102° to 106° C. (216° to 220° F.), and is retained here for some little time. This high heat is supposed to kill all the living bacteria that may be in the milk, even the resisting spores being commonly destroyed. While the milk is still in this apparatus, and before the chamber is opened, the bottles are sealed by a mechanical contrivance and then allowed to cool. After this they are taken out of the sterilizer, and are ready for distribution. The milk thus treated is sometimes pure white, although frequently it has acquired a brownish color, which is not enticing to one accustomed to ordinary milk. Moreover, it has a taste of cooked milk, which is to some people very unpleasant. But when the method is successful the milk contains no living bacteria, and may now be kept indefinitely without further change. It may be shipped to all parts of the world, and whenever opened it will be found still sweet. The process is evidently equivalent to the canning of fruit or meat, only more difficult because the milk commonly contains many resisting spores.

Such sterilized milk can be bought almost anywhere in Europe, and there is undoubtedly a growing demand for it. Where this or other sterilized milk is used it is claimed that very favorable results follow. Careful statistics have been collected as to the number of deaths among infants from diarrhoeal diseases, and it is found that in some cities the deaths from infants fed upon raw milk are nearly three times as great as among those fed upon sterilized milk. Of course, no typhoid epidemics can ever be traced to such milk, and in general its use seems to meet with decided favor.

There are, however, some serious objections to this method of treating milk, which have been and probably will continue to be sufficient to prevent its wide extension. The first is that such milk appears to be slightly less digestible than raw milk. Over this matter, however, there has been and still is a great diversity of opinion, and many claim that there is really no difference in the digestibility. It is a matter of comparatively little importance, however, at least for adults and healthy children, for the sterilized milk can be digested, and the slight difference in ease of digestion probably has little significance unless it be for weakly individuals. Secondly, the taste of the sterilized milk is that of boiled milk, and this is rather unpleasant to most people. Probably a majority of our people, if called upon to drink sterilized milk or none at all, would prefer to give it up entirely. This is really an almost insurmountable obstacle to the wide extension of the use of sterilized milk, at least for the present generation. Those who have accustomed themselves to the taste of raw milk will not drink sterilized milk, and, if they do not dare to drink it raw, will not drink it at all. If infants are brought up on sterilized milk the next generation may look upon the matter differently, since the taste can be cultivated.

The third objection to sterilized milk is its cost, which pretty effectually prevents its wide use. Here is probably the real reason why the sterilized-milk industry has not extended more rapidly than it has. The cost of the milk that has been subjected to the treatment above described is considerably above that of ordinary milk, and the size of the pocketbook is commonly a matter outweighing, with most people, even matters of health. When raw milk can be purchased at half the price of sterilized milk, or even for a cent or two less, it will be purchased almost uniformly by the bulk of people, rather than the more expensive sterilized milk. Thus it happens that, in spite of the fact that sterilized milk can be purchased easily in most European cities, the business is not a large one. Probably not one quart of sterilized milk is sold to a hundred quarts of raw milk, even in cities where the business is best developed.

There are some who think that this method of treating milk is soon to be recognized as a necessity, and that it will be shortly regarded as improper to drink raw milk as it is to eat raw pork. But the business has grown rather slowly. Most people prefer to purchase their milk raw at a cheaper price and then boil it themselves, if they do not forget it. There is, moreover, one rather serious criticism that is made against this sterilized milk. Even with the high temperature that is used, it is impossible to be sure that all bacteria spores are destroyed. In most cases they are killed, but occasionally, and indeed not infrequently, a lot of milk will contain resisting spores that the heat does not destroy. These few spores that are left may become serious, far more so than the bacteria in raw milk. After sterilization they begin to grow, and, since this milk is very commonly kept for many days before it is used, these germs have a chance to become very abundant in the milk and to produce profound chemical changes therein, in some cases actually developing poisons. The changes that thus occur may be such as to escape notice with the eye, since they do not curdle the milk, and they may even fail to affect the taste of the milk. Such milk is to all appearances good, and would be given to infants without hesitation. If it did contain the injurious products thus referred to the results would be serious. Some bacteriologists are convinced that not a few cases of serious sickness have been produced in this way. When the milk is used shortly after the sterilization this matter is of no importance, since the bacteria spores grow slowly. But sterilized milk is supposed to keep indefinitely, and is therefore likely to be preserved some time before using, giving abundant opportunity for these spores to grow.

For these several reasons there is developing a different method of dealing with the problem. It is the well-known process of _Pasteurization_. But although the process has been known for several years, its application to the milk business on a large scale is quite new. Pasteurization consists in heating the milk to a temperature of only about 68° to 85° C. (165° to 185° F.), leaving it at this temperature for a short time, and then rapidly cooling. The length of time required depends upon the temperature used, being, of course, shortest for the higher temperature, but it varies from some two minutes to half an hour. This moderate heat does not necessarily produce the cooked taste nor, as we shall see, does it involve an expense which need raise the price. The temperature, however, is not sufficient to destroy all bacteria, and for this reason is looked upon with disfavor by those who feel that what is needed is an absolute destruction of all bacteria. The Germans, who like to do things thoroughly, do not take readily to Pasteurization, and there are others besides Germans who insist that this treatment does not make the milk safe. But if one is looking for practical possibilities rather than theoretical success, there is perhaps at present more to be said in favor of Pasteurization than sterilization.

Pasteurization is found to be sufficient to destroy all the strictly pathogenic bacteria that are likely to be in milk. The germs of diphtheria and typhoid are killed, and even the tubercle bacillus is rendered innocuous by a few moments at a temperature of 75° C. The resisting spores above mentioned are of course not destroyed, and many other bacteria are left uninjured. But the bacteria which escape the heat are not strictly pathogenic, and do not grow in the body. If they produce any injury to the drinker it is because they grow in the milk and produce injurious chemical products there. They are only dangerous, therefore, after they have had an opportunity to grow in the milk for some time. This opportunity they do have, as we have seen, in sterilized milk, but they do not have the opportunity in Pasteurized milk. Pasteurized milk is not designed for keeping, and those who use it know that while the strictly pathogenic bacteria are killed the milk will not keep. It will remain sweet a little longer than raw milk, but it must be used at once. It must be treated just like fresh milk. Under these conditions the bacteria do not commonly have an opportunity of growing sufficiently to produce their poisonous products before the milk is consumed. Practically, then, these bacteria that resist the moderate heat of Pasteurization are of no serious importance in connection with the healthfulness of milk. Pasteurized milk has been deprived of all its strictly pathogenic bacteria, and the germs still left will commonly have no opportunity to grow very much before the milk is consumed. It is therefore the confident belief of many that Pasteurization is actually a safer method of treating milk than sterilization. Moreover, the results appear to be equally favorable, for Pasteurization is claimed to produce an effect upon diarrhoeal diseases equal to that of sterilization.

But the most important argument for Pasteurization seems to be that it is really practical, and can be introduced upon a scale vastly more extended than can sterilized milk. The practice of Pasteurizing milk has doubtless been followed not a little by private families, but from the very outset it has appeared that the proper method of dealing with the matter is to treat the milk at a general distributing center, rather than to depend upon the consumer to do it. Not a few devices have been suggested for accomplishing the purpose satisfactorily and rapidly. The machines invented are planned upon two different principles. In one plan the milk is placed in some large vessel holding many gallons and is here heated, commonly by steam coils. It is allowed to remain here at the desired temperature for twenty minutes to half an hour, and is then cooled. This method is necessarily slow--so slow, indeed, that it is impractical for use where large amounts of milk must be treated rapidly for general distribution. It probably could not be used for the milk supply of a city. The other method is called that of continuous flow. Here the milk is allowed to flow continuously over a heated surface, which brings it quickly to the desired temperature. It is kept hot for only a short time, however, and it then flows over a cooled surface, where the temperature is brought down again and the milk is finally delivered from the machine in a continuous stream of cooled milk. Great objections have been urged against this process, from the fact that it is not thorough. The milk is retained at the high temperature for such a short time that many of the bacteria are not killed. The Pasteurization is decidedly less thorough than by the other method. But here, again, before condemning the process it is necessary to consider its purpose. If it is to destroy all the bacteria, or as large a number of them as is possible, it is of course unsatisfactory. If, however, the purpose is to treat the milk cheaply and rapidly in such a manner as to remove the danger of disease distribution through, the milk supply, it would appear that such a method is perhaps satisfactory.

So far as can be determined, this method is efficient in destroying pathogenic bacteria. Its efficiency is of course dependent upon the length of time that the milk is retained at the high temperature, and this can be regulated by the rate of the flow of the milk through the machine. All evidence we have seems to point to the conclusion that a temperature of 75° C., continued for a few minutes only, so far destroys or weakens the pathogenic bacteria which are liable to be found in milk that they need not subsequently be feared as producing disease. Of course, there are pathogenic bacteria that are not destroyed by this temperature, but they are not likely to occur in milk. The germs of typhoid, diphtheria, and tuberculosis are probably rendered harmless by such treatment, and these are the chief pathogenic bacteria of milk. Moreover, the other bacteria are very greatly decreased in numbers, so that the dangers of intestinal troubles are at least much reduced. In hospitals where Pasteurization has been adopted the results are as favorable as with sterilization.

The great value of this plan is, however, that it is practical on a large scale. In Copenhagen it has been in practice for some three years very extensively. In Denmark the amount of tuberculosis among cows is very great, somewhat more than half the animals suffering from this disease. As a result the public milk supply is regarded with more suspicion than in countries where the disease is less. It is everywhere recommended that the milk be always boiled before using, but the bother of treating the milk thus daily makes people unwilling to do it, and it is doubtful whether the practice is as common as the physicians think necessary. Some three years ago a company was organized to meet the public demand for safe milk, and it has adopted plans by which it furnishes Pasteurized milk on a scale as extensive as that of the ordinary milk-supply companies. The company has devised and manufactured two large machines which receive the milk, Pasteurize it, and cool it in a constant stream, and are capable of treating two thousand quarts an hour. The milk received by the company is tested chemically and filtered, and then allowed to pass through one of these large machines. After this it is placed in glass bottles and sealed with the company's seal. The heating is done by steam, and the cooling by brine cooled by an ammonia cooling machine. The greatest care is taken in cleaning and sterilizing the bottles, an enormous chamber some twenty feet long and six feet in diameter being used for a sterilizer. Into this the washed bottles are placed, the chamber hermetically closed, and then superheated steam is turned in upon them. Everything connected with the establishment is conducted with the greatest attention to cleanliness, and upon a very large scale. The bottled milk is subsequently distributed in ordinary milk carts. A bacteriologist is constantly testing the efficiency of the machines by bacteriological examinations of the Pasteurized milk.

The most important feature in this undertaking is that the company furnishes the city with milk at the same price as that furnished by the other companies without Pasteurization. It seems strange that this can be done, for the Pasteurization of course costs something. But the explanation is essentially that heat is cheaper than cold. Because of the subsequent Pasteurization this company does not feel it necessary to demand that the milk should reach them in as cool a condition as is required by the other companies. While their business rivals insist that they shall receive milk not warmer than 4° C., this Pasteurizing company receives it as warm as 10° C., and this saving in the cooling largely pays for the Pasteurization. The mechanical bottling enables them to employ a cheaper grade of help than is necessary when the milk is peddled in carts.

The results of this endeavor to furnish safe milk are in quite decided contrast to those connected with sterilized milk. Sterilized milk has now been on the market for quite a number of years, but, in spite of the fact that it can be readily bought in most cities, the actual business is small. The largest milk-supply company in Europe has a demand for only a few hundred quarts per day. This company in Copenhagen offers to the public a milk which has the taste of fresh milk and which has been so treated as to have all pathogenic bacteria within it destroyed, and at the same time the other bacteria greatly reduced in number. This milk it sells at the same price as ordinary milk. As a result its business has rapidly grown, and instead of supplying a few hundred quarts it sells some thirty thousand daily, and the amount of milk handled is increasing with great rapidity. It probably sells more Pasteurized milk than all the sterilized milk sold in Europe.

It would thus seem that we have here actually a practical method of dealing with the new problem of the milk supply. That it is practical is manifest from the actual results in this institution in Copenhagen. Whether it is regarded as satisfactory will of course depend upon our standpoint. Those that insist that the milk must be freed from all danger, and hence deprived of all bacteria, will not regard this method as satisfactory. But probably every one will recognize that milk thus treated is very much safer than raw milk, and that dangers from typhoid epidemics and tuberculosis are removed, even if they do not admit that intestinal troubles are thus avoided.

There can be little doubt that the method would be successful in our own cities, but its success would depend upon the price at which the milk is sold. If the Pasteurized milk is sold for a price much higher than ordinary milk it will not be a commercial success, for the vast majority of people prefer to save the one or two cents per quart, and run the rather slight risk of trouble from the milk. If it can be sold in our cities, as in Copenhagen, for the same price or a price only slightly higher than that of ordinary milk, it is hardly doubtful that it would soon come into favor, for who would not prefer milk that is safe from disease germs if the price is the same? Already there are a few attempts in this direction in some of our cities, but as yet they are only in the beginning stage. Whether they will develop to a wide extent depends probably almost wholly upon the price at which the milk can be sold.

It would appear, then, that this method of Pasteurization by a central company offers the most hopeful solution of this feature of the problem which is growing with the growth of cities. The milk companies could probably arrange, without great expense, such a plan of Pasteurizing large amounts of milk. This only emphasizes the conclusion, already reached, that the most hopeful method of dealing with the problem in our cities is through properly organized companies that can handle milk on a large scale, and will do it conscientiously, and not wholly from the standpoint of money-making.

TEACHERS' SCHOOL OF SCIENCE.

BY FRANCES ZIRNGIEBEL.

[_Concluded._]

Parallel in time with the course in historical geology or paleontology was that in botany, under the leadership of Dr. Robert W. Greenleaf, a Boston physician, who in his student days had assisted Dr. Goodale and was at the time of giving these lessons Professor of Botany and Materia Medica at the Massachusetts College of Pharmacy. A growing interest in the study of botany in the schools, and Dr. Greenleaf's exceptional ability as a teacher, made the attendance at this class very large. After an hour's lecture the instructor and two assistants directed the observation of the specimens by the students, who were required to make sketches of the objects studied. The first set of lessons was similar to that given in the school by Dr. Goodale several years before, and was of a preparatory nature, including morphological, structural, and physiological botany.

The introductory lesson dealt with the relation of botany to its various subdivisions and to other studies. The meaning of morphology was illustrated by comparing the four plant members--root, stem, leaf, and plant hair--with the different plant organs, and a practical exercise, with specimens whose parts were sketched and labeled, was given to show that the position and mode of development of a part determine its rank as a member or structural division, while its function may give it quite a different rank as an organ.

A preliminary view of vegetable histology, considering the shape, wall, markings in the wall, and contents of cells, was next given. This was followed by lessons on vegetable physiology, in which the absorption of liquids and gases for the making of food, assimilation, transfer and storage of food, the growth of cells and tissues, the excretion of waste products, special kinds of work, as climbing, catching of insects, etc., reproduction, and the process of metabolism as illustrated in cells, were treated of first in a general way and then elaborated upon in the succeeding lessons. Much time was devoted to the anatomy, histology, and germination of seeds and to the structure and function of root, stem, and leaf. The morphology of fruits and their anatomical classification (profusely illustrated from the fruits of the market and neighboring fields), with a discussion of the contrivances for dissemination of fruits and seeds, furnished subject-matter for both a profitable and interesting lesson.

The last lessons of this set were devoted to the study of the flower and its parts, particularly stamens and pistils, and ended with an explanation of the processes of pollination and fertilization. The work of making vertical and horizontal plans of the flower served as an introduction for the second year's course on Systematic Botany, wherein the relations between the common families of flowering plants were shown. This course was illustrated by numerous hothouse flowers and also by dried specimens, of which one hundred kinds were given to each teacher. This course was given to teachers, many of whom could by means of a key analyze any common flower, but who knew nothing of the principles of plant relationship. The theories of special creation and of evolution were explained, and the theory of descent with variation was taken as a hypothesis.

Starting with this theory of evolution as a basis, the structure of certain families was studied and they were taken as types with which other related families were compared. After a classification of all known flowering plants into gymnosperms and angiosperms, and subdividing the latter into monocotyledons and dicotyledons, the lily family was considered as typical of monocotyledons. It and its related families afforded a simple means of demonstrating the problems under consideration. Members of this family were found to be characterized by having an endogenous stem, usually parallel veined leaves, six-parted perianth free from a three-celled superior ovary, and six stamens. The allied families were shown to agree with the type in the internal or fundamental characters, such as the number of carpels and cells of the ovary, but were found to differ in the more external or environmental characters, such as the arrangement of the parts of the perianth.

After studying the relations between the various groups of endogens, the trees and weeds of the apetalous division of exogens were next considered, and through _Ranunculaceæ_ connected with polypetalous dicotyledons. These latter were classified according to whether the parts of the flower were hypogenous, perigynous, or epigynous. These terms signify, respectively, under the pistil, around the pistil, and on the pistil. In this group the rose family presented several modifications of the pistil, according to which it was divided into tribes.

When the group of _Gamopetalæ_ was studied, _Solanaceæ_, the nightshade family, with its regular flower, and _Labiatæ_, or mint family, with irregular flower, were taken as types with superior ovaries. Various modifications from these types were found in several families.

_Ericaceæ_, the heath family, presented, in its suborders of _Ericineæ_, _Pyroleæ_, and _Monotropeæ_, which had superior ovaries, and _Vacciniæ_, which had inferior ovaries, an intermediate order between the preceding _superæ_ and following _inferæ_, of which latter group _Campanulaceæ_ was considered a type.

The relations between many families were traced, and the _Compositæ_ were lastly considered, this family showing the greatest differentiation with its coalescence of circles, adnation of different circles, reduction in parts, and number of individuals brought together. The greatest deviation from a simple flower and a complexity of structure were here presented. Through the co-operation of parts these flowers were of high physiological efficiency.

Throughout the course, families of medicinal or other economic value, or such as presented evidences of adaptation for cross-fertilization, dissemination of seed, life in desert regions, or contained examples of parasiticism or many poisonous genera, were incidentally considered.

Carefully made illustrated notebooks, collections of dried specimens, and other evidences of interest in the course were shown by the teachers, who gained great facility in placing an unknown flower in its proper family without the use of a key or botany.

The next set of lessons in the botanical series consisted of the usual number (fifteen) on cryptogamic botany. This was perhaps the course which was the most difficult of presentation; but, notwithstanding, much dried and fresh material, representing chiefly the higher cryptogams, was distributed among the pupils and examined by them.

The fourth and last year of the series was spent on paleobotany. This was a somewhat novel and valuable course, which was particularly appreciated by those who had studied geology and paleontology in other classes of the school. A large amount of laboratory material was provided from the museum. The duplicate fossil specimens of the society were used by the class, and ninety determined species were figured by many members. Since the close of these lessons persons who have shown throughout the four years a satisfactory knowledge of botany and have passed the examinations, in the most exhaustive course ever given in the subject for teachers, have received certificates stating their qualifications.

In the spring of 1887, owing to a suggestion made by Professor W. O. Crosby and to assistance furnished by him, a private course of instruction was arranged by Prof. G. H. Barton, of the Institute of Technology, for a series of lessons in field geology. Twenty-one persons, nearly all of whom had attended Professor Crosby's course in The Teachers' School of Science, took these lessons with great enthusiasm. The series of lessons was continued in the autumn, with the addition of twelve new members to the class. From this beginning has grown the systematic course of field instruction in geology now carried on as one of the regular courses. As at present conducted, it consists of a series of lessons in the autumn and spring of each year, so arranged as to give detailed instruction in methods of observation covering a range through all portions of the subject, embracing mineralogy, lithology, structural geology, historical geology, and physiography.

The method pursued is as follows: The class is taken to a typical place for illustrating the subject in hand. The area to be studied is pointed out, and then for a half hour or so the class is asked to make observations unassisted by the instructor and with as little communication among themselves as possible. Then they are called together and questions are asked to draw out the results of their observations, free discussion being invited at this time, and questions from the class answered by the instructor. Then the instructor explains the phenomena studied, and finally gives a general lecture upon the particular subject involved. Notes, taken in the field, are carried home and rewritten and then handed in at the next lesson, to be corrected and returned later. A printed synopsis is furnished each member of the class at every lesson, for which payment is made sufficient to cover the cost of the printing. Each member is also required to be provided with a hammer, chisel, and compass.

The course of instruction begins with a discussion of the general principles of erosion, and one lesson each is given at places illustrating an excess of chemical and mechanical action. At Medford a very broad dike of coarsely crystalline diabase, penetrated by numerous cracks, furnishes an exceptionally good opportunity for the observation of rapid chemical decomposition, an almost complete gradual transition being shown from the fresh unaltered rock through all degrees of decomposition to the formation of soil. The cause of the decomposition is explained, with the resulting products, and the history of the latter is traced till they form parts or the whole of a new rock. A drumlin is seen, at Great Head, Winthrop, being undermined and worn away by the waves. By comparison with other drumlins in the neighborhood, the original form of Great Head can be easily restored mentally and the effect of waves and currents upon a coast can be readily appreciated. In an excursion to North Adams and rides over the Hoosac Mountains and to the summit of Greylock, rivers are seen in their various stages of action, the cutting backward by the cascade action, the cutting downward of torrent action, and the more quiet transportation and final deposition of the streams passing through the lower levels and approaching the sea. From the sides of Hoosac and Greylock the surface of the Massachusetts plateau is seen, with its dissection by the Berkshire and Deerfield Valleys, illustrating the broad effects of erosion over the surface of the continent.

Passing next to a discussion of the disposition of the material that is derived by erosion from the land, a lecture upon the sorting action of water is given, and the resultant beds of gravel, sand, and clay are studied in a section cut by the Fitchburg Railroad through the sand plateau at Lake Walden, in Concord.

The next step is to study these products of deposition in their consolidated forms. At Parker Hill, Roxbury, a large quarry furnishes opportunity for the study of conglomerate, special attention being paid to the means of determination of stratification in a nearly homogeneous, coarse material. Here also is a large section in a drumlin left in a nearly vertical face by excavation about twenty years ago, and now illustrating finely the action of rain during the years. This forms an instructive contrast with the marine erosion of Great Head, Winthrop. Any one of the numerous slate quarries at Somerville serves the purpose of studying stratification in a fine, homogeneous material. In each of these three last-named places the various phenomena of stratified rocks are studied, such as unconformity, cross-bedding, ripple-marks, strike, and dip, but attention is confined more especially to the original structures, subsequent structures being left for later lessons.

Eruptive rocks are then taken up and studied in respect to their origin and original structures. The quarries near Winter Hill, in Somerville, furnish an admirable opportunity to study dikes. Here a small hill of slate is intersected by three series of dikes of different character and intersecting each other at various angles, enabling a determination of their relative ages. An intrusive bed, now separated from its parent dike by erosion, affords the means of comparing the characteristics of the two forms and of tracing out the relation between them. The inclined positions of the dike and bed and the numerous quarries furnish several sections in varying relations to the two. The various dikes and the inclined position of the inclosing slate give an excellent chance for the first instruction in the making of geological maps and sections. Notes are taken for this purpose, and both maps and sections are constructed and handed in at a later date.

At Marblehead Neck various other eruptive structures, such as flow structure, ancient ash-beds, etc., are seen in the felsite, of which many varieties occur there. Attention is especially called to the liability of mistaking flow structure for stratification, the similarities and differences being explained. At Marblehead Neck, also, a careful study is made of the formation of pebbles, all stages being shown from the dislodging of fragments from the cliffs by frost action, the dropping into reach of the waves, the first rounding of the sharp angles to the subangular outline, and finally the rounding of the fragment into a complete pebble form.

At Newton Centre a study of contemporaneous beds is made, including their relations to the inclosing rocks and a comparison of their characteristics with those of intrusive beds.

Eruptive masses, metamorphic rocks, and vein phenomena are all well shown at Fitchburg, where Rollstone Hill is an eruptive mass of granite cutting through the metamorphic mica schists and gneisses, and the granite in turn is cut by very numerous veins of pegmatite, abundantly rich in tourmaline crystals and occasionally having beryl.

Glacial structures are next taken up. At Newtonville is studied the esker and sand plateau, rendered famous by the work of Prof. W. M. Davis and others; at Clinton an exceptionally fine set of terraces, and the best example of _roches moutonnées_ near Boston, where a class can be taught in a very few minutes to recognize that the movement of the ice sheet must have been from the north toward the south; and at Stow and Haverhill are studied drumlins.

After this, special attention is devoted to the subsequent structures of rocks, such as folds, faults, cleavage, joints, etc. Typical places, as before, are selected for each, and the work carried on in the same manner. When this course has been entirely accomplished, then places of greater complexity and where the problems are not quite so plain are visited, and opportunity is given to exercise the skill or knowledge already gained.

Following this, a series of lessons is devoted to the study of typical places illustrating the various historical strata occurring in Massachusetts; among others, Nahant and Braintree for the Cambrian, Attleboro for the Carboniferous, Mount Holyoke for the Triassic, Gay Head for the Cretaceous and Tertiary, Rockport, Martha's Vineyard, and claypits of Cambridge for the Glacial Champlain.

The work in this course has been marked by enthusiasm, and the attendance has been very large, reaching a maximum of two hundred and ten, with an average attendance of seventy-one in the autumn of 1896. As a direct outcome of this work, and connected with it, several excursions to distant points have been made by parties under the charge of Professor Barton during the summer vacations. The most important of these were the following: A five-days' trip through western Massachusetts; a seven-weeks' trip to the Pacific coast, including visits to the Lake Superior copper regions, the Yellowstone Park, Butte, Montana, Great Shoshone Falls in Idaho, Columbia River, Mount Hood, Frazer Cañon in British Columbia, the Great Glacier of the Selkirks, and the Hot Springs at Banff; and two trips through Nova Scotia, one in 1894 and another in 1898. In each of the latter trips special attention has been paid to the various kinds of mining coal, iron, and gold, to the famous mineral localities like Cape Blomidon, and to the general geology.

Also, connected with this work, a special course of lessons has been given by Professor Barton each spring to a class from the Boston Normal School, and many occasional lectures and field lessons to the classes of the State Normal School at Framingham, and at other schools, teachers' clubs, etc. During the Boston exhibition of the cyclorama of the volcano of Kilauea, Hawaii, over three hundred teachers and a large number of schools visited that exhibition and listened to personal lectures by Professor Barton in direct connection with the work of The Teachers' School of Science.

Owing to the request of members of the field class, a private class was organized in the winter for a course of twelve lessons in mineralogy. This proving successful, and a demand for laboratory work being shown, this work was incorporated as a distinct course in the school. It was during the early part of this work that Professor Barton introduced for the first time in The Teachers' School of Science the system of daily and final examinations--a system since followed as the general practice of the school and now considered as one of its most fundamental features.

This course, after various experiments, has finally developed into a definite four-years' course of instruction, at the end of which those members who have met all the requirements receive the diploma of the school. The full four-years' course is designed to give a thorough training in the fundamental principles of geological science. Each year is given a series of fifteen lessons of two hours each, partly laboratory, partly lecture, and fully illustrated with specimens and diagrams. The first year's work is devoted to mineralogy. One introductory lecture is given on the principles of chemistry as the basis of understanding the composition of minerals, and the four following lessons are devoted to a study of the physical properties, mainly crystallography. During the remaining lessons, about one hundred and fifty of the commonest mineral species are studied, the class being required to learn to recognize each species and be able to tell its composition.

The second year's work with lithology is carried on largely in the same way as with mineralogy. At first a brief review is made of the most important rock-forming minerals. Then all the commoner species of rocks are taken up and studied, so as to learn to recognize each species at sight and to tell its composition. Besides this, lectures are given upon the origin of the rocks and the derivation of their component materials, involving a large amount of dynamical geology.