8 
Spirochaeta icterohaemorrhagiae 
long with 2 to 2J turns, these were by far the more numerous, and the other a 
longer, looser organism measuring 8 to 10/x with only two curves. The latter 
only constituted about 8 per cent, of the spirochaetes present. It is possible 
that some are shorter even than 4/x but I am at present uncertain about 
some very short organisms. 
Futaki, Takaki, Taniguchi and Osumi (1916, 1917), who discovered them 
first in the excised skin and lymph glands of two cases of rat-bite fever state 
that they “can be detected in about 3 % of house rats in Japan.” They 
describe the spirochaete which they have named S. morsus muris, as having 
a short thick body “somewhat larger than S. pallida but smaller than 
S. duttoni and obermeiri. It is thicker than S. pallida and measures T5 to 2p 
to 5 to 6/x,” generally thick and short of 2 to 5ft with a flagellum at one or 
both ends, with 1 \ to 6 curves. They state that the flagella may or may not 
be stained with Giemsa, but Burri’s Indian ink method shows them well. 
The spirochaetes found by me in rat 84 correspond very closely with 
their description, and although I cannot see distinct flagella (in Giemsa 
stained preparations) in most, in a few they are indistinctly made out. 
I would express here my indebtedness to Mr Jos. Cooper-Dean, and Mr 
T. B. Goodall, F.R.C.V.S. for their kindness in procuring specimens from 
the country and for their interest in the work. 
REFERENCES. 
Benian, T. H. C. (25. xi. 1916). Relief staining for Bacteria and Spirochaetes. Brit. Med. 
- Journal. 
Coles, A. C. (27. xi. 1915). An Easy Method of detecting S. pallida and other Spirochaetes. 
Ibid. 
Futaki, K., Takaki, F., Taniguchi, T. and Osumi, S. (ii. 1916). The cause of Rat-Bite 
Fever. Journ. Exper. Med. xxiii. 249-50. 
- (i. 1917). Spirochaeta morsus muris n.sp., the cause of Rat-Bite Fever. Second 
Paper. Ibid. xxv. 33-44. 
Ido, Y., Hoki, R., Ito, H. and Wani, H. (1. xi. 1916). The Prophylaxis of Weil’s Disease 
(Spirochaetosis Icterohaemorrhagica). Journ. Exper. Med. xxiv. 485-496. 
- (1. ix. 1917). The Rat as a carrier of Spirochaeta icterohaemorrhagiae, the causative 
agent of Weil’s Disease (Spirochaetosis Icterohaemorrhagica). Ibid. xxvr. 341. 
Jobling, J. W. and Eggstein, A. A. (xn. 1917). The wild Rats of the Southern States as 
carriers of Spirochaeta icterohaemorrhagiae. Med. Record, New York, xcii. 1096. 
Martin, L. and Pettit, A. (6. i. 1917). Presence de Sp. icterohaemorrhagiae chez le Surmulot 
de la zone des armees. C. R. Soc. Biol. lxxx. 10-11. Trop. Dis. Bull. ix. 360. 
Nicolle, C. and Blanc, G. (5. v. 1917). Premiere enquete sur 1’existence chez le rat de 
Tunis, des Spirochetes pathogenes pour le Cobaye. C. R. Soc. Biol. lxxx. 445-6. 
Trop. Dis. Bull. x. 275. 
Noguchi, H. (1. v. 1917). Spirochaeta icterohaemorrhagiae in American Wild Rats and its 
Relation to the Japanese and European strain. Journ. Exper. Med. xxv. 755. 
Stokes, A., Ryle, J. A. and Tytler, W. H. (27. i. 1917). Weil’s Disease (Spirochaetosis 
Icterohaemorrhagica) in the British Army in Flanders. Lancet, I. 
