OBSERVATIONS ON THE EFFECT OF VARIOUS CHEMICAL 
REAGENTS ON THE MORPHOLOGY OF SPIROCHAETES. 
By DORIS L. MACKINNON, B.Sc. 
{From the Quick Laboratory , Cambridge.) 
4 Figures. 
It has been stated 1 that in the stomach of the bed-bug the 
spirochaetes of relapsing-fever may frequently be observed to lose 
their normal regular curves and become more or less “ worm-like.” This 
is of interest to those who oppose the view that spirochaetes are rigid 
spirals, a view which, alter gradual abandonment by most observers, has 
lately been again advanced by Novy and Knapp in their study on S. 
recurrentis. 
It seems probable that the alteration in form may be due to the 
action of some constituent of the digestive juices of the bug. Professor 
Nuttall suggested to me that it might be possible to produce the same 
effect artificially by treating the living organism with various chemical 
reagents. In this attempt 1 was not altogether successful. Certain 
acids (notably formic acid) and quinine, and, in a lesser degree, glycerine, 
did cause a straightening out of the body and a corresponding flattening 
of its curves ; but the appearances could scarcely be described as “ worm¬ 
like.” They help, however, to combat the notion that the curves are 
rigid. 
In addition to the liquids just mentioned, and certain other drugs 
and acids, I subjected S. recurrentis to some of the reagents used by 
previous observers otr various spirochaetes in their attempts to decide 
the systematic position of these organisms. 
I employed S. recurrentis (Russian strain) in thin films of infected 
mouse-blood, mixed with equal parts of citrated salt solution. As a rule, 
1 Lowenthal (1905, Die Spiroehaeten, Biophysik. Centralbl. i.) quotes Schaudinn’s 
observations on this point. Klodnitsky (1907, Centralbl. f. Bakt. xnv. pp. 126-8) 
claims to have seen the same phenomenon. Nuttall has repeatedly observed it himself, 
but has expressed the opinion (1908, Parasitology, i. p. 144) that Klodnitsky’s photo¬ 
graphs show that that author was dealing with the spermatozoa of the bug, and not with 
altered spirochaetes. 
