34 The Philippine Journal of Science 1920 
acetone-insoluble extract of beef heart, 92, 66, and 77 per cent, 
respectively; at 8° C., 100, 92, and 88 per cent, respectively. 
The second subdivision, those probably syphilitic although not 
evidently so, consisted of 20 patients upon whom 25 tests were 
done with the following results: At 37° GS cholesterinized extract 
of beef heart, simple alcoholic extract of beef heart, and acetone- 
insoluble extract of beef heart, 84, 48, and 68 per cent, respec- 
tively ; at 8° C., 92, 88, and 80 per cent, respectively. 
We came then to another group of cases in which again there 
were no histories of syphilis nor of antisyphilitic treatment. In 
some of them the physical findings were rather vague and the 
clinical diagnoses not stated with any degree of assurance, but 
in others the findings were quite definitely not those of syphilis 
and the diagnoses were of conditions not syphilitic; such, for 
example, as acute articular rheumatism and typhus fever. In 
this group we had 16 patients with 16 tests. In all of these there 
was complete or partial fixation of complement with antigen 
cholesterinized extract of beef heart, either at 37° C. or at 8° C., 
or both, associated with absence of fixation with either of the 
other antigens. We feel rather confident that the cases in this 
last group were not syphilitic and that the complement fixation 
obtained in them was nonspecific. The cholesterin-reénforced 
antigen was the only one to give positive results in this group and 
it appeared to be more unreliable at the higher temperature than 
at the lower. 
There were 341 tests on 317 nonsyphilitics, in none of which 
was any degree of fixation obtained with any of the antigens 
under either condition of incubation. Thus, in 357 tests on 
333 nonsyphilitic patients the cholesterin-reénforced antigen 
gave positive results in 2.2 per cent at 37° C. and in 1.4 per 
cent at:8° C, 
As a result of these studies Doctor MacNeal and I were con- 
vinced, first, that the use of the cholesterinized antigen with 
first incubation at 8° C. for four hours constitutes a more sen- 
sitive test for syphilis than does any of the other methods exam- 
ined; secondly, that the cholesterinized antigen, both at 37° 
C. and at 8° C., is apt to yield nonspecific fixation. Therefore, 
in a diagnostic reaction, fixation with the cholesterinized an- 
tigen alone is at best of only doubtful significance. We were 
further convinced that the simple extract antigen, with the first 
incubation at 8° C., is more sensitive than the cholesterinized 
antigen at 37° C., and in this series it gave no false positive 
reactions, according to the available evidence. 
