412 



PATHOGENIC BACTERIA. 



Reservoir for toxin. 



Rubber tube. 



The amount of local reaction, edema, etc., the appetite 

 and general condition, the temperature-curve, and the 

 stability of the body-weight, must all be taken into con- 

 sideration, so that the administration shall not be too 

 rapid and the animal thrown into a condition of cachexia. 

 One of the principal things to be avoided is haste. Too 

 frequent or too large dosage is almost certain to kill the 



animal or bring about a con- 

 dition of hypersensitivity to 

 the toxin. 



Behring found that mixing 

 the toxin with trichlorid of 

 iodin lessened the irritant 

 effect upon susceptible ani- 

 mals. I prefer not to use 

 susceptible horses. 



As the antitoxin protects 

 the horse perfectly against 

 the toxin, it is said that a pre- 

 liminary dose, as suggested 

 by Pawlowski, will enable 

 one to omit all the small 

 preliminary doses of toxin, 

 and render the horse im- 

 mune at once. Thus, I have 

 frequently administered ioo 

 c.cm. of antitoxin of about 

 ioo units strength to a horse 

 one day and 500 c.cm. of strong toxin (500 factors) the 

 next. This is just 500 times as much toxin as has twice 

 killed a horse in the laboratory. After the lapse of a few 

 days the same quantity can be administered again, and in 

 a week a third time. In this rapid way antitoxin can often 

 be secured at short notice. I have not found this method 

 of any particular advantage. 



The possibility of producing serum rapidly may depend 

 upon the method, but the production of strong serums de- 

 pends chiefly upon the horse, and not upon its treatment. 



Pinch cock. 

 s Hypodermic needle. 



Fig. 87. — Apparatus used by the 

 author for injecting toxins into horses 

 by gravity. 



