680 EXPERIMENT STATION EECOED. 



The main object is said to have been that of the study of horse sicliness, es- 

 pecially the production of serum that would be free from hemolytic effect. This 

 is considered as having been accomplished since the results of the last experi- 

 ments resulted in a loss of but 3 per cent due to horse sickness. Biliary fever or 

 piroplasmosis of the horse, mule, and donkey has been determined to be due to 

 same species of Piroplasma. The native equines are said to be immune to the 

 disease while imported animals are susceptible. The disease is inoculable with 

 blood of an immune horse into a susceptible mule. The strongest immunity 

 against this disease may break down under the influence of a virulent fever 

 such as that of horse sickness. 



It has been determined that immune cattle do not carry East Coast fever in- 

 fection. Experiments indicate that it is possible to clean an infected area, even 

 when there are susceptible cattle running on it, if the cattle as soon as their 

 temperature rises are confined so that they are not allowed to drop ticks on 

 the pasture. 



From experiments conducted the author concludes that the natural transmis- 

 sion of spirillosis is due to the progeny of Rhipicephalus decoloratus that have 

 developed on cattle suffering with or immune from spirillosis. It was found 

 possible to inoculate spirillosis into susceptible cattle and sheep with the blood 

 of sick and immune animals. 



Results obtained from heartwater experiments are said to indicate that it is 

 possible to produce a serum which may be applied against the disease. Experi- 

 ments in immunizing sheep against blue tongue show that the serum of immune 

 sheep hyperimmunized to the extent of 500 cc. of virulent blood injected at 

 different intervals has highly developed protective qualities which it is thought 

 will permit of its use for practicable injection. Swine plague was for the first 

 time discovered in the colony. A swine fever or complication of swine fever 

 and swine plague also occurred. Bursattee, a wound disease caused by a hypho- 

 mycete and known in India among horses was observed in one case. As a re- 

 sult of preliminary dipping experiments the author recommends dipping as 

 a measure for cleaning a farm from ticks, but it should be carried out sys- 

 tematically and for a long period. Pleuro-pneumonia is considered to be on the 

 decrease. A herd of camels imported from Somaliland was destroyed having 

 been found infected with surra. 



Report of the government veterinary bacteriologist, A. Theiler (Transvaal 

 Dcpt. Ayr. Ann. Rpt. 1905-6, pp. 81-109). — A piroplasmosis which has been 

 determined as distinct from Piroplasma higcmmunt is here described as P. 

 mutans. It has been found that an animal can be infected with the former 

 singly and later with the latter. P. mutans has all the characteristics of P. 

 higemimim, as it remains in the immune animal and can be transmitted with the 

 blood. 



The inoculation of mules against horse sickness for the public was started 

 in November. During the year 2,325 mules were inoculated in the Transvaal 

 with a loss of 3.8 per cent from inoculation, while in Rhodesia 388 mules were 

 inoculated with a loss of 2.3 per cent. In connection with the injection of serum 

 it was found that various kinds of virus from immune animals were more viru- 

 lent than those in use. This is said to make it necessary to alter the method 

 of inoculation. Experiments undertaken to determine the possible role of 

 mosquitoes in the transmission of horse sickness failed, as it was not possible 

 to keep the mosquitoes alive in the stable. This, however, is said to be in 

 accordance with the tlieory that the disease is thus transmitted as stable 

 horses do not as a rule contract the disease. Equine piroplasmosis has been 



