IMMUNITY 275 



lack of power to increase or change the chemical activity of certain cells and 

 fluids of the body; immunity results from the possession of such power. 



It would, therefore, seem that idiosyncrasy is a manifestation of cellular 

 inability to respond to a need for increased or new chemical activity, that 

 allergy and anaphylaxis are manifestations of imperfect, inadequate response 

 and that active immunity is the result of adequate response to a need for greater 

 or more diversified chemical activity of certain tissue cells. 



Much is yet to be learned as to which cells produce antibodies, variations in 

 their response to different antigens and the exact chemical nature of various 

 antigen-antibody reactions. The application to these problems of better meth- 

 ods of studying colloidal changes and hydrogen ion concentration will extend 

 our knowledge of the mechanism of immunity and variations in response of the 

 host to antigens. 



Although the extensive studies of Victor Vaughan and Abderhalden have 

 not produced any new technique or working hypothesis that at present can be 

 applied in medical practice, they have disclosed many facts relative to the 

 chemical aspect of bacterial life and the presence of ferments in blood serum 

 that every immunologist and physician should become familiar with. 



ANIMAL INOCULATION 



Animal inoculations are occasionally helpful in establishing a diagnosis 

 when other means of investigation fail or are inadequate; they are indispensable 

 in attempts to detect and identify the offending organism in infectious diseases 

 of unknown origin and in the development of specific chemical preparations for 

 the alleviation, cure and prevention of diseases that afflict men and brutes; they 

 are essential to the production of specific sera that in diagnosis and treatment 

 curtail immeasurably the sufferings of man and beast. 



If one considers the sheep that have been saved from anthrax, the hogs 

 saved from cholera, the horses saved from lockjaw and animals of all sorts saved 

 from hydrophobia, as a direct result of animal inoculations, and compares this 

 with the total suffering inflicted upon dumb animals by man in his effort to 

 arrest disease, the conviction that these activities have lessened the sufferings 

 of brutes is unavoidable. 



Before one can procure desired results from animal inoculation tests in the 

 study of bacteriology several things are necessary familiarity with the appear- 

 ance and habits of experimental animals in health, the effect of sudden changes 

 of environment upon them, their normal rate of growth, the normal appearance 

 and relations of their internal organs, the diseases that occur spontaneously in 

 these animals and the changes they produce, and finally, the chain of events to 

 be expected when an animal has been inoculated with a particular species of 

 pathogenic bacteria. 



Postmortem examinations of experimental animals should be made 

 and recorded with the same care and detail and by the same general tech- 

 nique described in text books on human pathology in which direction will 

 also be found for the removal, fixation and staining of tissue for microscopic 

 examination. 



