366 SPECIFIC MICRO-ORGANISMS 



Tube No. i should show complete hemolysis early in the second 

 incubation. Tube No. 2 should remain free from hemolysis, or 

 show only a very slight amount at the end of the second incu- 

 bation. If these have behaved properly and the tests on the 

 known sera have resulted as they did when previously tested, 

 then the behavior of Tubes 3 and 4 is a measure of the amount of 

 lipoidophilic substance in the serum of the patient. One dis- 

 tinguishes about eight different grades of reaction, from complete 

 fixation (no trace of hemolysis) to no fixation (complete hemolysis) . 



The luetin test is performed by injecting 0.05 c.c. of luetin 

 intracutaneously in two places on the left arm and at the same 

 time 0.05 c.c. of a control suspension, consisting of the medium 

 without any growth of spirochetes, at two points on the right 

 arm. Local inflammation on the left arm, appearing in two to 

 ten days and sometimes resulting in the formation of a pustule, 

 is regarded as a positive test. The test is often negative in the 

 earlier stages of syphilis. H 



The various diagnostic tests for syphilis are now extensively em- 

 ployed. Microscopic search for the spirochete is of value in the 

 untreated primary and secondary stages. The complement-fixa- 

 tion test becomes positive a few weeks after the appearance of the 

 primary lesion and is generally regarded as indicating an active 

 syphilitic process. The luetin test may be positive in latent or 

 inactive syphilis when the Wassermann is negative. Further 

 experience with the luetin test is necessary in order to determine 

 its real significance. 



Spirochaeta (Treponema) Refringens. This is a relatively 

 gross spirochete which occurs in primary syphilitic lesions along 

 with Sp. pallida. It seems to have no pathogenic properties. 

 Noguchi 1 has obtained pure cultures of it and found them with- 

 out pathogenic properties for rabbits and monkeys. 



Spirochaeta (Treponema) Microdentium. 2 This is one of the 

 common spirals of the mouth. It may be confused with Sp. pal- 



1 Journ. Exp. Med., 1902, Vol. XV, p. 466. 



2 Noguchi: Journ. Exp. Med., Vol. XV, pp. 81-89. 



