1913] 



Sweet: Epithelioma of the Common Fowl 



33 



History of Virus 



1. Kept in test tube closed with cotton plug 



from May, 1909, to July, 1910 



2. Virus used in above after one passage 



through fowl 



3. Kept in test tube closed with cotton plug 



from May, 1906, to August, 1910 



4. Mixture of viruses. 



(a) Kept in test tube closed with cotton 



plug from May, 1906, to July, 1911, 



(b) Kept in same manner from August, 



1910, to July, 1911 



5. Virus used in No. 4 after one passage 



through fowl 



6. Virus used in No. 5 after an additional 



passage through a fowl 



7. Virus used in No. 6 after an additional 



passage through a fowl 



8. Powdered virus kept in open mortar from 



August, 1910, to July, 1911 



9. Virus received from Honolulu — freshly re- 



moved from infected fowls 



12. Blood from infected fowl, injected in- 

 travenously 



ubation period 

 in days 



(a) 3 



(b) 4 

 10 



(a) 4 



(b) 6 



(a) 4 



(b) 3 

 3 



Result, 



negative 



3 



10. Some virus in No. 9, given intravenously 8 to 12 



11. Virus used in No. 7, given intravenously 10 to 12 



Growth 

 Small 



Small and in- 

 creased in size 

 slowly 



10 



Lesion appear- 

 ing first on 

 mucous mem- 

 branes 



Growth in 



throat and on 



comb 



(a) 8 



(b) 3 

 i 



(a) 3 



(b) 3 



(a) 6 



(b) 1 

 6 



In those cases in which the incubation period was greatly 

 lengthened by an attenuation of the virulence of the virus, the 

 rate of growth was much slower, although the ultimate course 

 of the disease seemed to be but little changed, this being in accord 

 with the observations of Burnet (1906). 



Clinical Course. — When the disease is inoculated by scarify- 

 ing the comb and wattles there appear after varying periods of 

 inoculation, small, raised, whitish granulations at the points of 

 inoculation. In the early stages these granulations bear a con- 

 siderable resemblance to tubercles, but later become larger, firmer, 

 more circumscribed, and form a cauliflower-like tumor increasing 

 in size up to about the tenth day. On the tenth to the twelfth 

 day dry scabs form on the surface of the growth, and in the 

 following days the whole growth gradually' hardens into a crust, 

 becomes smaller, and at the end of two or three weeks is readily 



