EXPERIMENTS WITH VIRUS OF CATTLE PLAGUE. 167 



In carrying out the experiments to be detailed I made an attempt 

 to repeat the various methods employed by different workers, and am able 

 to report on the following: 



I. Filtration of bile. II. Filtration of blood diluted with salt solu- 

 tion. III. Filtration of blood laked with distilled water. IV. Filtra- 

 tion of peritoneal fluid. 



Throughout these tests great precautions were taken to prevent ac- 

 cidental infection of the experimental animals. In order fairly well to 

 exclude the possibility of their having been accidentally infected before 

 inoculation, the cattle were kept under observation in a fly-proof stable 

 for at least seven days. If during this time no symptoms manifested 

 themselves the animals were inoculated. Two control animals, A and 

 B, were kept with each experiment. A received unfiltered material, 

 while B remained uninoculated. Animal A was isolated in a fly-proof 

 shed, animal B remained with those that were inoculated with filtrate. 

 Animals that did not contract cattle plague from the filtrate were after- 

 wards tested for immunity with virulent blood. The animals used were 

 from Sibuyan Island as, so far, animals immune to cattle plague have 

 not been encountered among cattle from that point. 



EXPERIMENTAL. 



No. 1. — The bile was collected and mixed with an equal part of phys- 

 iological salt solution during the post-mortem examination on an animal 

 bled to death for virulent blood. The mixture was divided into four 

 parts, designated as a, b, c, and d. Part a was not filtered, 6 was passed 

 through a Berkefeld filter V, c was filtered through a Berkefeld candle 

 N, and d was passed through one marked W. 



Four animals, Nos. 1, 2, 3, and 4 were inoculated. 



Animal No. 1 received 50 cubic centimeters of part a under the skin. On the 

 seventh day after the inoculation the temperature rose and the animal died of 

 cattle plague on the thirteenth day. (See Chart No. 1.) 



Animal No. 2 was injected with 50 cubic centimeters of b. Cattle plague did 

 not follow. (See Chart No. 2.) Nineteen days later 10 cubic centimeters of 

 virulent blood was given subcutaneously. In four days the animal sickened with 

 cattle plague and was bled to death for virulent blood on the sixth day after 

 inoculation. (See Chart No. 2'.) 



Animal No. 3 received 50 cubic centimeters of c. It remained well. (See 

 Chart No. 3.) Twenty days later it was inoculated with 10 cubic centimeters 

 of virulent blood; it sickened with cattle plague three days later and was bled 

 to death on the sixth day. (See Chart No. 3'.) 



Animal No. J/ inoculated with 50 cubic centimeters of d, remained well. (See 

 Chart No. 4.) After sixteen days it received 10 cubic centimeters of virulent 

 blood, it sickened with cattle plague on the fourth day and was bled to death on 

 the tenth after inoculation. (See Chart No. 4'). 



