Malarial Horse-Sickness. 279 



In the case of two horses which developed very severe fever, 

 their blood, when mixed and inoculated intravenously into a clean 

 horse, produced virulent Horse-sickness ending fatally. 



It has formerly been shown that the blood of virulent Horse- 

 sickness, when diluted with water and filtered through a Pasteur 

 filter, is still virulent to horses. Thus the microbe in such blood 

 must be infinitely minute. 



Therefore, my experiments show that the parasite of the malarial 

 form must be evolved from an infinitely small pre-existing extra- 

 i rpuscular form. 



The foregoing facts which were announced in the report referred 

 iO evoked some criticism in the direction of suggesting that another 

 disease had gained access to my stables or on the other hand that 

 the animals possessed the parasites already in their systems previous 

 to being inoculated by me. 



With a view to meeting these contentions and demonstrating in 

 an incontrovertible manner the correctness of the former results, the 

 following experiments were devised and carried out. 



Immediately after the former experiments I obtained a number 

 of horses from this area and six were placed in a new iron compound. 



The same manner of inoculation was followed by the production 

 of parasites somewhat sparingly in numbers in four of the animals. 



During the following year the stables of the Institute were 

 thoroughly cleansed with hot caustic potash solution (i %) which 

 was applied to every portion of the buildings by means of a powerful 

 spray. Every crevice was very carefully washed out and after the 

 place had been allowed to become thoroughly dry the same process, 

 using however i % of Schering's Formalin, was applied. 



All woodwork was put in a sound condition and the concrete 

 floor was gone over very thoroughly by masons. 



After these matters had been accomplished I obtained through 

 the kindness of the Militar)- authorities, at the request of the Honour- 

 able the Colonial Secretar}-, ten clean horses which had been recently 

 landed at Port Elizabeth. 



These were sent up by train, were brought straight to the Institute 

 and were immediately placed into stalls. 



Each horse had a special bucket for water which was filled into 

 them and they were fed with drj- forage. 



Previous to attempting any inoculation of the animals they were 

 kept in the stables for several weeks during which their temperatures 

 were taken daily on five occasions and their blood frequently examined 

 for any abnormality. 



Horse 27. Was inoculated with 20 c.c. of the blood of '' salted " 

 Horse B (which had been inoculated ten days previously with 10 c.c. 

 of preserved virulent blood taken originally from a horse dying of 

 virulent horse-sickness) on the 4th December 1902. The temperature 

 began to rise on the eighth day and on the tenth day parasites were 

 found in the blood. 



Horse 28. This animal w^as inoculated at the same time as the 

 last but was kept in another stable. Its temperature began to rise 



