ANIMAL EXPERIMENTS 



117 



remaining oxygen. There are many other ingenious mechanical 

 ways of growing bacteria under anaerobic conditions and the student 

 is referred to works devoted entirely to technic. 



FIG. 37. Novy jar. 



Animal Experiments. 



To determine the pathogenicity of bacteria; to measure the 

 strength of toxins and anti-toxins, to standardize anti-toxins, and to 

 recover bacteria in pure culture, it is often imperative that small 

 laboratory animals be used. Guinea pigs, rabbits, and mice are 

 oftenest employed. Strong young animals are the best. Culture 

 toxins and pathological material are intoduced into their bodies 

 in various ways. A favorite one is to shave the abdomen, scour it 

 with soap and water, and then bichloride of mercury, and finally 

 sterile water. With a pair of sterile scissors a small hole is cut in 

 the abdominal parieties and through it a loop containing a drop of 



