282 
Urethral Sp iroch aetos is 
Waves. The bodies of most of the spirochaetes showed a number 
of curves or waves, but in all the preparations examined there were 
a few coiled forms and some simple curved or bow-shaped organisms 
without waves. 
The actual number of waves varied. In the first place as was 
only natural the longer individuals possessed on the average more 
waves than the shorter ones, some of the pre-division forms showing 
certainly ten. A spirochaete of the average length, about 11 /a, had 
as a rule 4 or 5 waves. 
The number of waves depended also to some extent on the thickness 
of the spirochaete as has been observed by Fantham. The relatively 
broad parasites generally had the body bent into fewer and wider 
curves than the more slender forms. 
But even making all due allowance for length and thickness there 
still remained many variations. The rate of motion and the character 
of the movements at the moment of fixation probably accounted for 
most of these. As has already been pointed out the most actively 
moving spirochaetes showed vigorous lashing movements which obscured 
the curves of the body. Such parasites when suddenly fixed would 
presumably show a contorted outline, and in stained preparations it 
was in just such contorted spirochaetes that the waves were often 
fewest (see fig. I, 45-50). The less active spirochaetes, especially 
those showing only rotatory movements, were frequently stretched 
out in a straight line or slightly bent by undulant movements and 
showed a considerable number of waves. In stained films it was 
observed in accordance with this that the straight or but slightly 
bent spirochaetes showed the greatest number of waves. 
In every preparation of the fresh urethral discharge there were a 
number of quiescent or dead spirochaetes, and by exposure to the 
temperature of the air or by heating all the organisms could be killed. 
These dead or quiescent spirochaetes always showed a considerable 
number of waves whether they were examined as wet preparations 
or after fixation and staining, but there was a marked difference between 
those that had been killed rapidly and those that had died slowly. 
Practically no difference could be made out between the spirochaetes 
killed by heat and those found in smears of pus obtained at the same 
time but immediately fixed and stained. In similar preparations which 
had been kept at the laboratory temperature, however, and in which 
all the spirochaetes had in consequence died (a process which took 
about eight hours), nearly all the organisms were linear in outline 
