78 Proceedings of the Royal Irish Academy. 



The Sinrocluete, — A thin, undulating, thread-like organism, staining bluish 

 pink with Giemsa's solution. It possesses most often five undulations, which 

 are not steep. It is pointed at each extremity, to which it gradually tapers, 

 and no cilia have been noted either at the extremities or along the length of 

 the parasite. In some organisms there is an appearance as of a nucleus-like 

 body placed rather towards one end. It is slightly redder in colour than the 

 remainder of the organism, and sometimes is vesicular, and bounded by a 

 reddened border limiting it. In some cases the organism contains a number 

 of metachromatic bodies, as mentioned later. The organism observed in 

 hanging-drop, and unstained, is slightly motile, the change in position being 

 apparently due to contraction of the organism along its length, the undula- 

 tions shortening. In stained films I estimate the length at about 17/x on an 

 average, and the thickness at about "S/.t ; the length and thickness of the 

 parasites appear to be fairly constant. The spirocheetes are external to the 

 cells ; in no case have they with certainty been observed in the interior of 

 timiour-cells. The spirochsetes may be single or entwined ; and from the 

 specimens I have examined I believe that they divide transversely into 

 two individuals after increasing in length. Xo undulating; membrane is 

 present. 



In addition to the spirochetes, are other bodies, first, I believe, described 

 by Krzysztalowicz and Siedlecki^ in films prepared from a case of human 

 syphilis. A very striking object in the films is a long, bacillus-like body, 

 which is more or less stiff and straight, pointed at each extremity, and 

 stained light-blue with dark-red granules placed at almost regular intervals 

 along its length. This body is non-motile, and appears to have some 

 relationship with the spirocha^te, because it is invariably found, in my 

 experience, with spirochaetes, not only in these dog-tumours, but also in 

 other cases where I have demonstrated a spirocheete (case of a rat without 

 trypanosomiasis, and in a young puppy, in the exudate of a fatal peritonitis). 

 These organisms increase in length, and the metachromatic granules become 

 further apart; and at the same time the organisms become thinner and 

 more attenuated. In certain cases I have seen an appearance highly 

 suggestive of their being converted into spirochaetes, because, ha^dng become 

 much attenuated, they become undulating and sinuous in outline. Moreover, 

 in certain examples of undoubted spirocheetes, there is an e^udent meta- 

 chromatism, red-stained granules being present in the body of the spirochsete. 

 "Without giving an absolute and positive opinion, I am strongly inclined to 

 consider these bodies as stages in the development of the spirochsetes. .- 



1 Ki'zysztaloAvicz and Siedlecki : Contribution a I'etude de la stnicture et du cycle evolutif 

 de Spirochsete pallida.— Bulletin International de I'Academie des Sciences de Cacorie. 



