EXPERIMENTS WITH CYTOST 111 



Dec. 10. Gray hair becoming more and more pronounced in the 

 patches of once dense black hair. Most marked in tail. Daily 

 injections continued. 



Feb. 4, 1922. Weight, 2270 gms. Black hair on head replaced by 

 white hair. Injections continued. 



Feb. 8. Weight, 2170 gms. Cat weak, anterior incoordination, eye 

 discharge. Daily injections continued until March 15, 1923. 



March 17, 1923. Cat died. Weight, 2050 gms. Autopsy per- 

 formed five minutes after death. 



Autopsy: Lungs, chronic fibrous pneumonia; heart, hyper- 

 trophied, dilated; liver, fatty degeneration; stomach, full of 

 erosions, dilated, fibrosis; intestines, fibrosis, erosion, begin- 

 ning ulcers; kidneys, chronic nephritis; adrenals, enlarged; 

 bones, extremely brittle; brain and cord, congested; aorta and 

 arteries, hard. 



In no instance has the writer been able to elicit such 

 degenerative tissue changes by the injection of similar 

 quantities of heterologous cytost — that is, cytost pre- 

 pared from the tissues of animals of another species. 

 Even cytost prepared from a lion's muscle, when in- 

 jected in similar fashion into cats, does not lead to any 

 pronounced pathology such as induced by that pre- 

 pared from cats' tissue. 



In various experiments in which parallel groups 

 of animals have been injected with homologous and 

 heterologous cytost, only those treated with the former 

 exhibit such tissue changes as have been described 

 above. 



It will be recalled that in the experiments with the 

 kittens mentioned a few pages back, kitten "A," which 

 received cytost injections spaced a week apart, gained 

 in weight more rapidly than its litter mates. This sug- 

 gests that, in small quantity, cytost may actually be 

 capable of accelerating the metabolism of the tissue 

 cells. In order to test this conclusion a series of mature 



