236 SURRA. 



Avith small blood-spots. The peritoneal and pericardial cavities 

 have been found to contain layers of lymph. The other in- 

 ternal organs are generally free from macroscopic alteration, 

 except that occasionally a sodden appearance of tissue is met 

 with — the result of effusion into connective structures. It is 

 in the microscopic examination of the blood of animals suffer- 

 ing from surra that our attention is drawn to the presence of 

 certain organisms which give speciality to the condition. 

 When a small quantity of fresh blood is placed on a slide, and 

 viewed with the aid of a six-inch power, the parasite — which may 

 be present singly or in groups — is observed to possess a some- 

 what rounded body, inclining to a neck, surmounted by a 

 spheroidal head, and a tail tapering to a long flagellum. In 

 both cervical and caudal regions there is a papilla-like eminence. 

 In length it is about three or four times the diameter of a 

 white corpuscle. In colour it appears to be white. Closely 

 watched, interesting movements are noticed. The filarial seem 

 to have a special affinity for the red corpuscles : one, two, or 

 even more, after wriggling about the field of the microscope, 

 become attached to a red corpuscle, and appear to be tugging 

 at it until disintegration takes place. This disposition towards 

 white corpuscles is never noticed ; but these are in the disease 

 supposed to increase in number. 



In order to observe these phenomena, it is essential that 

 fresh blood be used. 



From the tabulated records of Mr. Evans, there would 

 appear to be some relation between the febrile symptoms of 

 the disease and the appearance of the parasites in the blood- 

 stream ; and that when these are most numerous, the tem- 

 perature is in proportion much elevated. 



In the blood of animals which had six days previously been 

 inoculated with blood from surra patients, there were to be 

 seen swarms of the parasites ; while the same result followed 

 the examination of blood of horses which had drunk surra 

 blood seven and a half days previously. Blood which has been 

 drawn from the affected living animal, twenty-four hours before 

 the experiment, has proved incapable of producing the disease 

 by introduction into the body by any of the foregoing means. 



Inoculation of blood containing the parasite into the dog 

 was successful in one instance. 



