262 BACTERIOLOGY FOR NURSES 



may be obtained by first washing the lesion with sterile water 

 and drying it with sterile gauze. Part of the base of the ulcer 

 is then scraped with a curette until the superficial tissue is removed 

 and blood appears. The blood is wiped off with sterile gauze until 

 clear serum begins to ooze. A drop of the serum mixed with a drop 

 of distilled water is placed on a coverslip, which is then inverted 

 over a hollow slide as a hanging drop. Examined with the dark- 

 stage illumination the organisms may be distinctly seen as brightly 

 illumined objects on a dark background. Films may also be 

 prepared and stained as already described. 



Luetin. Noguchi has prepared an extract from pure cultures 

 of T. pallidum to which he has given the name of " luetin," which 

 gives a characteristic reaction in syphilitic individuals. The 

 reaction is analogous to the tuberculosis reaction in tuberculosis. 



Wassermann Reaction. The complement fixation test devised 

 by Wassermann, Neisser, and Bruck, whereby the presence of 

 specific antibodies in serum of syphilitic individuals may be de- 

 tected, is described in Chapter XIV. The test is widely used and 

 gives a positive reaction in over 90 per cent of active cases. It is 

 practically always present during the second stage and tends to 

 disappear as the disease becomes latent or is cured. 



T. PERTENUE 



A spiral organism was found by Castellani in 1906 in frambesia 

 or " yaws," a disease occurring in tropical countries. The lesions 

 seem to be analogous to those of syphilis, and by some writers the 

 diseases are considered identical ; other observers have found 

 that the antibodies produced against the two organisms differ, 

 and that consequently they are distinct species, and yaws cannot 

 on this account be considered as a mild form of syphilis. 



S. ICTEROHEMORRHAGI^ 



In 1915 Inada, Ido, and other Japanese workers demonstrated 

 the presence of a spirochete, to which they gave the name S. ictero- 



