463 
ON THE LIFE-CYCLE OF SPIROCHAETA^ 
GALLINARUM. 
PRELIMINARY NOTE. 
By E. HINDLE, 
Beit Memorial Research Fellow. 
{From the Laboratories of Professors Mesnil and Marchoux, 
Institut Pasteur, Paris; and the Quick Laboratory, Cambridge.) 
(With 5 Figures and Diagram in Text.) 
During the past two years I have been working on the morphology 
and life-history of Spirochaeta duttoni and, although successful in 
tracing parts of the life-cycle of this parasite, yet the work has been 
accompanied by many difficulties owing to the large percentage of ticks 
that are immune to infection. 
Whilst working at the Institut Pasteur, Professor Marchoux kindly 
placed at my disposal a plentiful supply of Argas persicus infected with 
Spirochaeta gallinarum and, therefore, having such good opportunities 
of studying this parasite in both of its natural hosts, I took up the study 
of this closely related species and have been successful in following the 
main features of its life-cycle. * 
As, however, certain confirmatory evidence as to the true relationships 
of the spirochaetes is not complete and, moreover, is liable to be delayed, 
it has been thought advisable to publish the main results which have 
been obtained in the form of a preliminary note. 
Two strains of Spirochaeta gallinarum have been employed in the 
following work. For the earlier observations the original strain of 
1 In employing the term Spirochaeta instead of Treponema we do not thereby express 
disagreement with the scheme of classification proposed by Dobell (1911). This point will 
be considered in a later communication. 
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