Malarial Horse-Sickness. 281 



horses. I now took a well kept horse which is used for riding purposes 

 and which had been " salted "' about six years ago. With the except- 

 ion of the fever which it had when being " salted " this animal has 

 always been in the best of health. 1. therefore, inoculated it with 

 20 c.c. of blood which shewed innumerable parasites. No fever in 

 the slightest degree was produced and no trace of i)arasites was to 

 be found. 



Horse jj. I bled a clean goat, and with its blood inoculated 

 horse 35 with 20 c.c. Xo result followed. 



1 thereafter inoculated the goat with 10 c.c. of preserve<l virulent 

 horse-sickness blood and ten days later the goat was bled. Being 

 somewhat afraid that the inoculation of the blood might prove fatal 

 (one cannot ever be certain of the reaction of horse-sickness passed 

 through either donkeys, oxen or goats) I mixed it with sterile glycerine 

 and water, and twenty-four hours later I inoculated horse 35 with 10 

 c.c. Some irregularity of temperature was at once set up. due most 

 probably to local irritation of the foreign blood but as at the tenth 

 dav no real rise had occurred I re-bled the goat and inoculated 10 c.c. 

 of the fresh blood into the horse. On the 12th day after, the 

 temperature began to rise and on the 13th day parasites were found 

 in the blood fairly numerously. Conclusions. These experiments 

 therefore enable me to conclude as follows. 



I. The blood of " salted " horses which have been regularly 

 re-inoculated for several months (10 c.c. lieing u.sed once a month) 

 is dangerous to inoculate into clean horses if the blood is drawn ten 

 or twelve days after the last inoculation. The former experiments 

 were conducted in this manner and as a result several animals died. 



II. If " salted " horses are rested for a few months and then 

 re-inoculated with 10 c.c. of preserved blood, their blood, if drawn 

 ten or twelve davs later will set up a satisfactory fever without much 

 risk. 



III. The blood of "salted ■ horses which have not been 

 inoculated for several months will also set up a reaction but the result 

 will be irregular and uncertain. 



IV. Horses which have been running in the c^oast areas near 

 .\lbanv may resist the inoculation of the blood of " sailed "' horses 

 even when the latter bloo<l is derived from animals which have been 

 recentlv re-inoculated. 



V. Blood taken from such animals as just staled, i.e. unsalted 

 horses which resist inocnilation with "salted "" blood, does not give 

 such an infection in clean horses as the blood of salted horses, even 

 although the latter have not been inoculated for a period of a year. 



VT. The blood of horse-sickness when passed through animals 

 which are either naturally insusceptible such as the ilonkey. ox and 

 goat, or animals which have acquired protection (sailed horses) 

 c(tnve\s a modifieci infection of horse-sickness which is malarial in 

 tvpe. and which is accompanied by the production of malarial 

 parasites within the red corpuscles of the animal which is inoculated. 



