PRESIDENTIAL ADDRESS. Ws 
forming a sub-order of the Order Coccidiomorpha under 
the Telosporidia. Het has worked out the evolution of 
Sarcocystis muris in the intestinal cells of the mouse. John- 
ston and I* have recorded S. muris in the muscles of E. rat- 
tus and E. norvegicus in Sydney. 
SPIROCHZTES.—The proper classificatory position of the 
spirochetes and allied organisms is a matter of much con- 
troversy. Some workers consider they are Schizomycetes or 
closely allied to the bacteria, basing their opinion chiefly 
on the occurrence of transverse division. Others consider 
them as protozoa, and complicated life-phases agreeing 
therewith have evén been described. The group is of vast 
human interest, inasmuch as one of the direst of human 
diseases—syphilis—is due to Treponema pallidum (Spiro- 
chaeta pallida), whilst several other fatal human com- 
plaints, in two of which rats probably play the part of 
normal hosts for the parasites, are due to other spiro- 
chetes. A digression as regards these organisms may 
therefore be allowed. | 
First of all it may be mentioned that spirochete-like 
forms are found in many ‘situations in man and animals, 
living usually a more or less saprophytic existence. Thus 
in man they are common in the mouth round the teeth, 
especially decayed ones, whilst Sp. refringens is found un- 
der the prepuce. Johnston and myself (loc. cit.) have re- 
corded as Sp. ratii, spirochetes found in the ceca of LE. 
norvegicus and E. rattus in Sydney. I have recorded? 
. abundant spirochetes in the centres of castration tumours 
in pigs in Western Australia, possibly dwelling in this situ- 
ation as imprisoned saprophytes. Sydney Dodd‘ has found 
them in ulcers of the skin in pigs in the Transvaal, and I 
+ Crawley, loc. cit., May, 1914, p. 432. 
2 Johnston and Cleland, Proc. Linn. Soc., N.S.W., 1909, p. 510. 
* Cleland, Parasitology, I., Oct., 1908. - 
mPodd, Jo: Comp, Path.,) Sx, 1906, py 206: 
H—May 1, 1918. 
