i t 



Discussion. 



Horse 264. — Tliroughoiit all the tests the haemolytic index was 

 higher for mules than for horses. It decreased for mules in four months 

 in spite of intercedent injection, increased however for horses, although 

 the horse was not bled. There still remained a haemolytic power for 

 mules in the serum ten months after the last injection. 



Horse 301. — This serum was also more haemolytic for mules than for 

 horses, similaiiy to that of horses 612 and 264. The haemolytic index of 

 serum 301 for mules and horses decreased in four months notwithstand- 

 ing 3,000 c.c. more blood had been injected and the horse had not been 

 bled. The serum still proved to be haemolytic for mule blood ten 

 months after the last hyperimmunisation. (Compare h. 264.) 



Serum of horse 398 was more haemolytic for mules than for horses. 



Gomparative Table. 



Conclusions. 



1. Three horses hyperimmunised with deflbrinated virulent mule 



blood gave a serum with stronger haemolytic properties for 

 mule than for horse blood. 



2. In two cases the serum preserved its haemolytic power for 



ten months. 



3. The haemolytic index (a) decreased in spite of further blood 



injections for mules and horses (301), (V) increased with 

 regard to horses, decreased with regard to mules within four 

 months, in which time one injection took place (264). 

 4 The haemolytic index is again not dependent on the quantity 

 of blood used for hyperimmunisation and the number of 

 injections. 



