22 VACCINE AND SEEUM THEEAPY 



body there must be an excess of complement, and 

 vice versa, in the serum if its immunising power is to 

 be effective. 



If any or all of the above conditions occur in the 

 serum of an animal, we have the ex^Dlanation why a 

 more or less mild and often chronic bacterial infection 

 may suddenly become acute and highly virulent, 

 thereby causing death. Similarly may also be ex- 

 plained the good results very often obtained by the 

 old-fashioned method of bleeding as a therapeutic 

 method of treating disease. By removing a certain 

 quantity of blood, we also remove a certain quantity 

 of immune body, thereby either preventing the 

 formation of anti-amboceptors or the deviation of 

 the complement. I will give some clinical cases to 

 illustrate these points. 



1. Cow ill with puerperal fever. This animal was 

 treated medicinally, to which there was no response, 

 and the cow died within forty-eight hours of my first 

 seeing her. The owner of this cow had several others 

 on the point of calving. Against my advice he 

 allowed four more to calve in the same house in which 

 the previous one died. These four developed the 

 disease in a virulent form. One of these I treated 

 medicinally, as in the former case, and three I treated 

 in the following manner. From the jugular vein of 

 each cow I removed 2 quarts of blood. Immediately 

 afterwards I removed 6 pints of blood from each 

 of four healthy cows. This blood was received 

 into a glass jar containing some normal saline in 



