ENDOCRINE FUNCTION OF THE THYMUS GLAND 335 



«. IMMUNIZATION OF THE CHICKEN WITH THE RED CORPUSCLES 

 OF THE ALBINO RAT 



Since I found that the combination of the albino rat and rabbit 

 for the preparation of any strong cytolysin (antithymus, anti- 

 testis, and hemolytic sera) is not a very favorable one, I thought 

 it would be worth while to follow the same plan of experiment, 

 but use some other animal than the rabbit as the serum producer. 



Before using the chicken as the antithymus serum producer, 

 we tried to get some information regarding the activity with 

 which the chicken reacts toward the injection of the red cor- 

 puscles of rat blood. Previous to the first injection of washed 

 red cells the normal chicken serum was examined as to its hemo- 

 lytic power against rat blood, and it was found that 0.3 cc. of 

 1 : 3 dilution of it is able to hemolyze 0.5 cc. of a 2 per cent 

 suspension of washed rat corpuscles. A 5 per cent suspension 

 of washed red corpuscles of rat blood was used as the antigen, 

 and 2 cc. of that suspension was injected intraperitoneally into 

 the chicken three times, at intervals of one week. 



A fresh sample of serum, taken just before the third injection, 

 was examined for its hemolytic power. A slight positive hemoly- 

 sis was obtained with 0.4 cc. of 1 : 10 dilution of the active im- 

 mune chicken serum with 0.5 cc. of 2 per cent rat corpuscles 

 suspension. The potency of the fresh immune chicken serum is 

 therefore somewhat higher than the fresh normal chicken serum. 

 Inactive immune chicken serum alone sho\^s no hemolysis against 

 rat corpuscles. 



The same sample blood serum as before, but inactivated, 

 shows, when tested for its hemolytic power with normal guinea- 

 pig serum as complement, an entirely negative result. More- 

 over, fresh normal rat serum used with inactive chicken immune 

 serum cannot cause any positive hemolysis. 



The serum of this chicken, taken eight days after the last in- 

 jection, shows negative hemolysis either with normal guinea-pig 

 serum as complement or with normal rat serum, against washed 

 rat corpuscles. We have to assume, therefore, if we suppose that 

 some hemolysin production has taken place in the chicken by the 

 injection of rat corpuscles, which seems to be very likely from 



