232 PATHOGENIC BACTERIA. 



a still larger one, and the increase is continued every eight 

 days or so, according to the condition of the animal, 

 until enormous quantities 300 c.cm. are introduced at 

 a time. 



The toxin causes some local reaction at first a dis- 

 tinct inflammation, later a painful edema and a febrile 

 reaction. The amount of local irritation is much less 

 marked when the injections are made slowly ; and a 

 gravity apparatus, which is filled with the amount of 

 serum to be injected, suspended from the ceiling of the 

 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 300 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 

 animals. 



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. 



The Preparation of the Serum for Therapeutic Pur- 

 poses. When, because of the tolerance to large quanti- 

 ties of toxin, the horse seems to possess antitoxic blood, 

 a " twitch" is applied to the upper lip, the eyes are 

 blindfolded, a small incision is made through the skin, a 

 trocar thrust into the jugular vein, and the blood allowed 

 to flow through a cannulated tube into sterile bottles. It 



