34 TRYPANOSOMA 
parasite in the blood of horses, mules and camels which were 
suffermg from a disease known as Surra, and which was 
extremely fatal to these animals in the Punjaub and British 
Brumah. In 1885, Veterinary Surgeon Steele further investi- 
gated the same disease and found the parasites in all cases, 
moreover both Evans and Steele proved by numerous experi- 
ments, that by means of subcetaneous inoculation and by 
the introduction into the stomach of blood containing the para- 
sites the disease was transmitted to healthy animals. In 
1882 Certes demonstrated the presence of Trypanosomas 
in body fluids of certain oysters. In 1883 micro-organisms 
similar to those found in the rat were observed by Mitrophanow 
as occurring in the blood of mud fish and the German carp. 
In 1885 B. Danilewsky discovered Trypanosoma in the 
blood of birds, including ducks, geese, and fowls. 
In 1886 Professor E. M. Crookshank very materially 
added to our knowledge of these organisms by investigating 
the morphology and life history of the Trypanosoma which 
he discovered in about 24 per cent. of the London sewer rats, 
and in the following year he succeeded in producing some 
excellent photo-micrographs, which clearly showed the pre- 
sence of the flagellum, the dorsal undulating membrane, 
and the pulsating vacuole. In 1895 Dr. David Bruce an- 
nounced the very important discovery that the tsetse fly 
disease, or Nagana, in Zululand was caused by a Trypanosoma, 
For over three years Bruce very closely studied the disease 
and conducted a series of interesting investigations, in which 
he not only brought to light many new morphological char- 
acters of the organism, but demonstrated its presence in the 
blood of horses, mules, asses, cattle, buffaloes, antelopes, 
camels, hyenas, and dogs; moreover from all these animals 
the organisms were transmissible to such experimental 
animals as the cat, rat, mouse, rabbit, hedgehog. donkey, 
bosch-bok, hybrid of zebra, gumea pig, goat, sheep, monkey, 
and weasel. He also proved that under natural conditions, 
the disease was transmitted from animal to animal solely by 
the tsetse fly (glossina moritans). 
After Bruce’s researches the subject of Trypanosomiasis 
was taken up and studied in various parts of the world, but 
