x Contents 



PART II. 



THE PRECIPITINS. 

 SECTION I. METHODS : PAGE 



Treating rabbits for the production of precipitating antisera . . .51 



Modes of injecting (p. 57), marking rabbits (p. 58), weighing the 

 animals (p. 58), when to kill the treated animals (p. 59). 



Killing the animals and storing the antisera 59 



The choice of animals for immunization 61 



Collecting bloods and testing them with antisera 62 



Sources of error in precipitin tests 72 



Opalescent antisera (p. 72), over-powerful and weak antisera (p. 74), 

 suitable dilutions of bloods tested (p. 74), effects of preservatives on 

 antisera (p. 76), acid or alkaline reaction of the medium (p. 79), in- 

 jurious effects of acids and strong alkalies and salts (p. 81), precautions 

 with regard to quantitative tests (p. 86), bacterial development (p. 86). 



SECTION II. THE NATURE OF PRECIPITIN REACTIONS 88 



Inactivated haematosera, " precipitoids " non-reactivatability of haema- 



tosera immune-bodies in haematosera 90 



The nature of precipitins and precipitable substances . . 96 



The precipitum (p. 99), macroscopic and microscopic appearances 

 during reaction (p. 100), the supernatant fluid (p. 101), the influence 

 of salts upon the reaction (p. 102), regarding the claim that pre- 

 cipitins permit of distinguishing the different albumins of the same 

 animal (p. 104), the effect of tryptic and peptic digestion upon the 

 interacting bodies (p. Ill), regarding the supposed precipitins for 

 peptones (p. 112), influence of temperature upon the reaction (p. 113), 

 influence of heat upon the interacting bodies (p. 114), effect of filtra- 

 tion on normal sera (p. 118), effect of putrefaction and desiccation 

 (p. 119), stability of antisera and sera in vitro (p. 123). 



SECTION III. OBSERVATIONS UPON PRECIPITINS AND PRECIPITABLB SUB- 

 STANCES in Corpore 126 



SECTION IV. THE SPECIFICITY OF PRECIPITINS 134 



The selective action of precipitins in blood-mixtures (p. 140), 

 measurement of degrees of reaction (p. 141), the delicacy of the test 

 (p. 144), the strength of antisera (p. 144), differences in degrees of 

 reaction of individual bloods (p. 145), character of precipitins formed 

 in different species of animals treated with the same blood (p. 146). 



SECTION V. ISOPHECIPITINS, ANTIPRECIPITIXS, NORMAL PRECIPITINS, AUTO- 



PRECIPITINS 148 



SECTION VI. QUALITATIVE TESTS WITH PRECIPITINS, INCLUDING SUMMARY 

 OF LITERATURE AND PERSONAL RESULTS : 



1. Phytoprecipitins 152 



Bacterioprecipitins (p. 152), Yeast precipitins (p. 154), Precipitins 

 for albumins of higher plants (wheat, roborat, ricin, crotin) (p. 155). 



