Staining yig 



It is very slender, measuring from 0.33 to 0.5 fi in breadth to 3.5 

 to iS-S M in length (Levaditi and Mcintosh). 



It forms no spores. Multiplication seems to take place by 

 longitudinal division. 



It is motile, and when observed aUve with a dark field illuminator, 

 can be seen to rotate slowly about its longitudinal axis at the same 

 time that it slowly sways from side to side with a serpentine move- 

 ment. The organisms are provided with flagella at one end, some- 

 times one at each end. 



Noguchi* observed two types of treponema, one slender, one 

 stouter. When carried through culture and used to inoculate rabbits 

 their differences were found to be fairly constant. The lesions pro- 

 duced in rabbit's testicles varied with the variety of organism in- 

 oculated, one causing a diffuse, the other a nodular, orchitis. He 

 conjectured that the distinction may be of value in explaining certain 

 obscure points in human syphilis. 



Staining. — /. Films. — The original discovery of the organism 

 was achieved through the employment of Giemsa's stain — a modifi- 

 cation of the Romanowsky method. But by this method the organ- 

 isms appeared very pale and not very numerous. Goldhornf 

 improved it as follows: 



In 200 cc. of water, 2 grams of lithium carbonate are dissolved and 2 grams of 

 Merck's medicinal, Griibler's BX, or Koch's rectified methylene blue added. 

 This mixture is heated moderately in a rice boiler until a rich polychrome has 

 formed. To determine this a sample is examined in a test-tube every few minutes 

 by holding it against an artificial light. As soon as a distinctly red color is 

 obtained, the desired degree of heating has been reached. After cooling it is 

 filtered through cotton in a funnel. To one-half of this polychrome solution 5 per 

 cent, of acetic acid is gradually added until a strip of litmus-paper shows above 

 the hne of demarcation a distinct acid reaction, when the remaining half of the 

 solution is added, so as to carry the reaction back to a low degree of alkalinity. A 

 weak eosin solution is now prepared, approximately 0.5 per cent. French eosin, 

 and this is added gradually while the mixture is being stirred until a filtered sam- 

 ple shows the filtrate to be of a pale bluish color with a slight fluorescence. The 

 mixture is allowed to stand for one day and then filtered. The precipitate which 

 has separated is collected on a double piece of filter-paper and dried at room tem- 

 perature (heating spoils it). When completely dried it can easily be removed 

 from the paper and may then be dissolved without further washingin commercial 

 (not pure) wood alcohol. The solution should be allowed to stand a day, then 

 filtered. The strength of this alcoholic solution is approximately i per cent. _ To 

 use the stain, one drops upon an unfixed spread enough dye to cover it, permits it 

 to act for three or four seconds, and then pours it off and introduces the glass 

 slowly, spread side down, into clean water, where it is held for another four or five 

 seconds, after which it is shaken to and fro in the water to wash it. It is next 

 dried and examined at once or after mounting in balsam. The spirochsetes 

 appear violet in color. 



GhoreyebJ recommends the following rapid method of staining 

 the organism in smears. A thin spread is to be preferred. No heat 

 fixation is necessary: 



* "Journal of Experimental Medicine," 191 2, xv. No. 2, p. 201. 



t Ibid., 1906, VIII, p. 451. 



I "Jour. Amer. Med. Assoc," May 7, ipro, Liv, No. 19, p. 1498. 



