534 Infective Jaundice 



straight body with one or both ends curved in the form of a semicircle, 

 the length of the hook at the end varying from 3-5 m. In motion the 

 organism, without relaxing its elementary windings, rotates upon its 

 axis two to four times per second, giving the impression of a drawn 

 out figure eight. The movement is bipolar and the direction al- 

 ternates at short intervals. When passing through a semi-sohd 

 medium such as fibrin or soft agar the body of the spirochaeta 

 assumes a wavy spiral not unhke S. refringens. 



Noguchi who has studied the morphology of the organism with 

 great care finds the body to be absolutely flexible. There is a dis- 

 tinct halo about it but no membrane has been demonstrated. 

 The part of the body which forms the hook terminates in a fine 

 point, but no minute flagellum-Hke projection can be demonstrated 

 by staining or by dark field illumination. Noguchi found it to be 

 devoid of a terminal filament such as characterizes Treponema and 

 is resistant to 10 per cent, saponin solutions, in which it is unlike 

 all other spirochaetae, and believes that it should be placed in a new 

 genus for which he suggests the name Leptospira. Martin, Pettit 

 and Vaudremer* describe flagella, terminally placed and varying in 

 number and length and terminating in tiny knobs. 



The hooked ends form one of the most characteristic poses of the 

 .organism while rotating on its axis in a free space, but as soon as it 

 meets a solid or semi-solid obstacle, it begins to penetrate into it. 

 Its habitat seems to be at porous gelatinous substance, the organisms 

 swarming in and out of it. 



Staining. — The organism may be colored by Giemsa's or Roman- 

 owsky's stains and appears pinkish purple, not taking the color 

 intensely. Burri's Indian ink method gives good results on smear 

 preparations, but Hume and Bedsonf think that smears are best 

 stained by Fontana's method which consists of treating the fixed 

 smear with a mordant consisting of 5 per cent, aqueous solution of 

 tannic acid and then applying an ammoniated silver nitrate solution. 



For staining the organism in sections of tissue, the older method 

 suggested by Levaditi for staining Treponema pallidum {q.v.) is said 

 to be most satisfactory. 



Isolation and Cultivation. — The organism was first obtained in 

 pure culture by Inada, Ido, Hoki, Kaneko and Ito,t the method 

 employed being that of Noguchi for Treponema pallidum. They 

 employed guinea-pig instead of rabbit kidney and always used liquid 

 paraffines. The most important part was the temperature. The 

 usual incubation temperature of 37°C. was found to be inappropriate, 

 the organisms becoming sluggish in two or three days and then de- 

 generating and disappearing from the culture media. The best 

 results were obtained between 22° and 25°C. 



* C. R. de la Soc. de Biol., 1916, lxxix,"io53. 

 t B. M. J., Sept. IS, 1917, n, p. 345. 

 t Jour. Exp. Med., 1916, xxrv, p. 387. 



