604 TREPONEMATA, SPIRONEMATA, LEPTOSPIRATA 
found in the saliva of infected rats, and they are not common in the 
urine. The bile and feces do not contain them. 
It is believed that the natural method of transmission from rat to 
rat is through wounds incidental to fighting. About 5 per cent of 
rats in Oriental countries are said to be infected. The disease has 
been transmitted through the bite of infected rats from rat to guinea- 
pig and from rat to rat. 
Ido, Ito, Wani and Okuda^ have found that the serum of convales- 
cents has a specific lytic action upon Spirochseta morsus-murium 
and apparently such a serum has some protective power against infec- 
tion. These observations have been confirmed by Kusama, Koba- 
yashi and Kasai,^ who have showai also that the homologous serum 
and the spirochetse exhibit Pfeiffer's phenomenon. 
Other organisms have been isolated from individuals bitten by rats. 
Blake'' isolated a streptothrix (Streptothrix muris rattse) from a case. 
Tunnicliff and Mayer/ and Dick and TunnicliflF / also cultured strepto- 
thrices from patients, the latter after the bite of a weazel. Douglas, 
Colebrook and Fleming'' have found streptococci in rat bite wounds. 
It is not improbable that the apparent confusion with respect to 
etiology arises from some lack of definiteness in the clinical symptoma- 
tology between a rat bite as such with its attendant infection, and the 
peculiar disease characterized by the name of rat-bite fever. 
The spirochete of rat-bite fever may prove to be identical with 
several spiral organisms described earlier. Of these. Spirillum muri 
of Carter,^ Spirochfeta laverani of Breinl and Kinghorn,^ and Spiro- 
cha?ta muris of Wenyon,^ as well as the organism described by ]\Iac- 
Neal, Mezinescu and Dietzer^" possess many points of resemblance. 
SEVEN-DAY FEVER. 
Nanukayami Fever. 
Seven-day fever is a disease described by Ido, Ito and Wani^^ as 
occurring in the rural but not the urban districts of the province of 
Fukuoka in Japan. In many respects it resembles Weil's disease; 
indeed, it has been regarded by many as atypical infectious jaundice. 
The onset is abrupt, with fever, glandular swelling, muscular pain, 
digestive disturbance, and early leukocytosis and albuminuria. Jaun- 
dice, however, is typically inconspicuous or absent. The infective 
agent, Spirochseta hebdomadis,^^ was found to be carried by the Jap- 
anese field mouse, Microtus montebelli. Morphologically, Leptospira 
1 .Jour. Exp. Med., 1917, 26, 377. - Loc. cit. 
3 Loc. cit. " Jour. Infec. Dis., 1918, 23, 555. 
5 Ibid., 23, 183. 6 Lancet, 1918, i, 253. 
' Ser. Mem. Med. Off. Am. India, 1887, 3, 45. « Lancet, 1906, ii, 651. 
9 Jour. Hyg., 1906, 6, 580. 
'» Proc. Soc. Exp. Biol., 1907. 4, 125. " Jour. Exp. Med., 1918, 28, 435. 
'2 Ido and his associates named the organism first "Spirochaeta nanykayami." It 
probably belongs to the genus Leptospira; hence, the name is tentatively Leptospira 
hehdomadis. 
