MICHIGAN ACADEMY OF SCIENCE. 
25 
therefore, are entirely independent parasites. The fact that no trypano- 
some may be found in the blood of an animal bv direct observation, even 
after the most careful search, is no proof of the absence of flagellates. 
A positive culture under such conditions is conclusive evidence as to 
their presence. Notwithstanding this fact, recent workers such as Eosen- 
busch and Mayer, by isolating cultures of flagellates from the blood of 
owls, and from the gut of mosquitoes which have fed upon such owls, 
believe that they have confirmed Schaudinn’s conclusions. 
Of considerably more importance was the work of Schaudinn with the 
second blood parasite of the owl, known as Leucocytozoon Ziemanni. 
This parasite he believed to be the resting stage of a very large trypano- 
some, and that, on fertilization, it developed in the gut of the mosquito 
into innumerable slender flagellates or spirochetes. These spirochetes 
were believed by him, at the time, to have the structure of trypanosomes 
from which they differed, however, in the mode of agglutination. Our 
investigations have shown that these views, like those regarding the 
lialteridium, are untenable. 
The most important result of these studies on the parasites of the 
owl was, without doubt, the special training which Schaudinn thus ac- 
quired. The skill and technique developed in the study of these organ- 
isms which seemingly possess but a purely scientific interest was 
utilized, a few months later, in the enduring research which resulted in 
the discovery of the cause of syphilis (1905). This was the crowning 
achievement of his life and it is truly regrettable that this indefatigable 
worked did not live to witness the practical results which followed so 
closely upon his discovery. 
The Spirochaeta pallida , the cause of syphilis, is a delicate spiral, 
motile organism which is placed by some among the protozoa, by others 
among the bacteria. The question of its systematic position is of rela- 
tively little importance at present. It is, however, reasonably certain 
that the spirochetes do not possess, as has been claimed, the structure 
of trypanosomes. 
The discovery of the germ of syphilis developed an intense interest in 
other spirillar diseases of man and the lower animals. It is not sur- 
prising, therefore, that our meagre knowledge regarding the .spirochete 
infections was rapidly widened. While it has not been possible as yet 
to cultivate these organisms there can be no doubt but that this will 
l>e accomplished in the near future. At the present time, the organisms 
can be maintained in the laboratory only by continuous passage through 
susceptible animals. This is especially true of the various strains of 
spirochetes which cause relapsing fever in man and somewhat similar 
diseases in chickens and geese. 
TRYPANOSOMES. 
Among the protozoa there is no more interesting group of parasites 
than that of the flagellates or trypanosomes. Their extremely common 
occurrence, the ease with which many of the pathogenic forms can be 
maintained in laboratory animals, and the fact that many of these 
organism's can be cultivated in the test-tube render them objects of 
special interest. This is all the more evident when it is borne in mind 
that in the tropics many diseases of animals, and even of man, are due 
to organisms of this group. 
