Chapter II: Preface: To the Second Edition

The principal change to note in this edition of the LEGAL CHEMISTRY is the addition of a chapter on Tea and its Adulteration. The general interest at present evinced concerning this species of sophistication appeared to call for a simple and concise method of examination which would include the requisite tests without entering upon an exhaustive treatment of the subject. The translator's practical experience in the testing of tea at the United States Laboratory of this city has enabled him to make a few suggestions in this regard which, he trusts, may be of use to those interested in food-analysis. Numerous additions have also been made to the bibliographical appendix.

J. P. B.

CONTENTS.

PAGE
INTRODUCTION 5

METHODS OF DESTRUCTION OF THE ORGANIC SUBSTANCES

By means of Nitric Acid 8

" " Sulphuric Acid 9

" " Nitrate of Potassa 10

" " Potassa and Nitrate of Lime 12

" " Potassa and Nitric Acid 12

" " Chlorate of Potassa 13

" " Chlorine 13

" " _Aqua Regia_ 14

Dialysis 15

DETECTION OF POISONS, THE PRESENCE OF WHICH IS SUSPECTED.

Detection of Arsenic 17

_Method used prior to Marsh's test_ 17

_Marsh's test_ 21

_Raspail's test_ 29

_Reinsch's test_ 30

Detection of Antimony 30

_Flandin and Danger's apparatus_ 32

_Naquet's apparatus_ 34

Detection of Mercury 36

_Smithson's pile_ 36

_Flandin and Danger's apparatus_ 37

Detection of Phosphorus 39

_Orfila's method_ 39

_Mistcherlich's method_ 40

_Dusart's method, as modified by Blondlot_ 40

_Fresenius and Neubauer's method_ 42

_Detection of Phosphorus by means of bisulphide of carbon_ 43

_Detection of Phosphorous Acid_ 45

_Estimation of Phosphorus_ 45

Detection of Acids 46

_Hydrochloric Acid_ 46

_Nitric_ " 47

_Sulphuric Acid_ 47

_Phosphoric_ " 48

_Oxalic_ " 49

_Acetic_ " 49

_Hydrocyanic_ " 50

Detection of alkalies and alkaline earths 52

Detection of chlorine, bromine and iodine 54

_Chlorine and Bleaching Chlorides_ 54

_Bromine_ 55

_Iodine_ 56

Detection of Metals 56

Detection of alkaloids and some ill-defined organic substances 65

_Stas's method_ 65

" " _as modified by Otto_ 69

" " " " _Uslar and Erdman_ 70

_Rodgers and Girdwood's method_ 71

_Prollius's method_ 72

_Graham and Hofman's method_ 73

_Application of Dialysis in the detection of Alkaloids_ 74

_Identification of the Alkaloid_ 74

_Identification of Digitaline, Picrotoxine and Colchicine_ 80

METHOD TO BE EMPLOYED WHEN NO CLEW TO THE NATURE OF THE
POISON PRESENT CAN BE OBTAINED 85

Indicative tests 86

Determinative tests 94

MISCELLANEOUS EXAMINATIONS 96

Determination of the nature and color of the hair and beard 96

_Determination of the color of the hair and beard_ 96

_Determination of the nature of the hair_ 99

Examination of Fire-arms 100

_The gun is provided with a flint-lock and was charged with
ordinary powder_ 100

_The gun is not provided with a flint-lock_ 103

Detection of human remains in the ashes of a fire-place 104

Examination of writings 105

Examination of writings, in cases where a sympathetic ink has
been used 110

Falsification of coins and alloys 112

Examination of alimentary and pharmaceutical substances 114

_Flour and Bread_ 114

_Fixed Oils_ 128

_a Olive Oil intended for table use_ 128

_b Olive Oil intended for manufacturing purposes_ 130

_c Hempseed Oil_ 130

_Tea_ 130

_Milk_ 137

_Wine_ 142

_Vinegar_ 147

_Sulphate of Quinine_ 148

Examination of blood stains 150

Examination of spermatic stains 158