DIPHTHERIA. 301 



stable so that the toxin is allowed to take its own time 

 to enter the tissues, can be recommended. Sometimes 

 it takes an hour to inject 500 c.cm. in this manner. 



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 be thrown into a condition of 

 cachexia with toxic instead of antitoxic blood. 



One of the principal things to be avoided is haste. 

 Too frequent or too large dosage is almost certain to kill 

 the animal. 



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. 



The suggestion of Prof. Pearson, that the large doses 

 of toxin might with readiness be introduced into the 

 trachea when the absorption is good, has been success- 

 fully accomplished by the author. The absorption seems 

 to take place without any change in the toxin, and to be 

 as rapid as from the subcutaneous tissue. 



As the antitoxin protects the horse perfectly against 

 the toxin, a preliminary dose will enable one to omit all 

 the small preliminary doses of toxin, and render the 

 horse immune at once. Thus, I have frequently adminis- 

 tered 100 c.cm. of antitoxin of about 100 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. It is yet 

 a question, however, whether this method, modified from 

 Pawlowski, is as good and certain as the slow way sug- 

 gested by Behring. 



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. 



