Animal Diseases. 269 



The two previously inoculated animals remained meanwhile in 

 seemingly good health. 



Experiment 2. — To prove that Goats Nos. 252 and 265, through 

 which the virus had been transmitted while in a non-virulent form, 

 were in no degree protected thereby against subsequent inoculation 

 with virulent virus. 



Goat No. 266 was inoculated on October loth with 100 c.c. of 

 the blood of 265 by subcutaneous injection and with 20 c.c. in- 

 jected intravenously. 



On the 8th day the temperature ran up to io5'4. 



On the nth day the temperature ran up to io4'8. 



On the 1 2th day the temperature ran up to 106 "4. 



On the 13th day the temperature ran up to io4'4, when it died 

 of Heart-water. 



Note. — During the progress of these experiments clean goats 

 were always kept with the experimental ones, and at the close of the 

 experiments they were all inoculated with virulent blood, and all 

 died of Heart-water.) 



Goat No. 252, which had been inoculated as already seen with 

 non- virulent blood, was now inoculated on the 23rd October with 

 30 c.c. of the blood of No. 266 by intravenous injection. 



On the 6th day the temperature rose to 104' 4. 



On the 7th day the temperature rose to 107 "6. 



On the 8th day the temperature rose to 107 "4. 



On the 9th day the temperature rose to io6'6, when it died of 

 typical Heart-water. 



Goat No. 258, which also had been already inoculated 28 days 

 previously with non-virulent blood, was now inoculated on October 

 23rd with 30 c.c. of the blood of 266 by intravenous injection. 



On the 7th day the temperature rose to 107*4. 



On the 8th day the temperature rose to io3'6, when the animal 

 died of typical Heart-water. 



Goats Nos. 278 and 279 were each inoculated in the same 

 manner as controls, and in both cases the temperature began to rise 

 on the 8th day afterward, and death occurred on the nth. 



In the above experiment, therefore, it is seen that the virus, 

 which had originally passed through Goats Nos. 252 and 258, and 

 was by that means raised to virulence, actually killed these animals 

 when re-inoculated into them after its accession to virulence had 

 been achieved. 



Hence Heart-water virus of which the virulence has been 

 lowered does not necessarily afford protection to animals which have 

 been inoculated with it. 



Experiment j. — To prove, in such cases as those of animals 

 Nos. 252 and 258, that an inoculation with weakened virus actually 

 predisposes to subsequent infection with virulent blood. 



In both of the above cases it is to be noticed that the incubation 

 period was shortened as compared with the " control " animals, and 

 I have further to add that this observation has been abundantly 

 confirmed in a vast number of other cases. 



