RErORT OF THE DePAETMENT OF AGRICULTURE. 531 



still proceeding-, and it is hoped to issue a relial)Ie hlack quarter 

 vaccine in liquid fmin vluring' the coming year. 



Nagana. — The officer in charge of the experimental station in 

 ]N"tambanana Settlement, near Empangeiii, Zululand. which had been 

 started for the study of nagaua, was severely handicapped at first by 

 lack of accommodation, but in the course of the year his efforts were 

 attended by a large measure of success. In trying the various reme- 

 dies that had been recommended, it was found that tartar emetic gave 

 very good results. This ireatmerit lias now been applied on a very 

 extensive scale to the cattle of the settlers, with the result that the 

 mortality from nagana has been reduced to a very low figure. Some 

 other important points were settled in the course of these investiga- 

 tions. It was observed that there were more than one species of 

 trypanosome responsible for the disease in Zululand, the small species 

 {Trypanosoma congolense) causing the greatest trouble in cattle. The 

 investigations are being continued. 



Horse sickness. — Of a total lurmber of 2413 mules inoculated 

 against horsesickness the mortality was about one per cent., con- 

 sidered very satisfactory indeed. Investigations into ! lie inoculation 

 of horses were continued with the object of making the nietiiod safer 

 and simpler. Although it has not been possible so far to simplify the 

 method to any apprecialde extent, considerable progress can be 

 reported in reducing mortality. Amongst the horses treated at 

 Ojiderstepoort according to this improved "method, the mortality was 

 reduced to 2" 5 per cent. 



The inoculation of horses for private owners, which had to be 

 abandoned for hnancinl reasons, was restarted. The conditions 

 governing the inoculation were amended so as to give preference to 

 bona fide farmers who wished to ha\e their riding or transport horses 

 inoculated. The maximum valuation now accepted is £15 per horse. 

 The fee for inoculation amounts to £5 per head, which includes the 

 cost of feeding and stabling the animal for a period of four to six 

 weeks, but excludes transport expenses which must still be borne 

 by the farmer. In the event of the horse dying as a result of horse- 

 sickness, compensation to the fixed amount of £15 is paid. Some 

 further experiments weie undertaken with the object of elucidating 

 the cause of staggers. Although a few cases of this disease appeared 

 among the horses m one experiment, it is not possible as yet to 

 produce the disease at will, and its ultimate cause is still obscure. 



Dourine. — The serological test for this disease was introduced 

 and found to give good results. The value of the test lies in the fact 

 that by means of it, cases can be detected before they show clinical 

 symptoms of the disease, thus making it possible to remove or destroy 

 such animals before they have done much harm; and secondly, that 

 in doubtful clinical cases it is possible through the test to decide 

 whether the animal is suffering from dourine ^r not. Experiments 

 on the treatment of the disease are being undertaken. 



Studies on the NorviaJ and Diseased Blood of Horses. — These 

 were conducted by one of the research officers and yielded soine very 

 interesting' results. It was found tliat sex, food, water, etc., had 

 practically no influence on the number of red corpuscles in the blood, 

 whereas the number differed very markedly with the mode of life of 



