SPIRONEMA RECURRENT IS 593 
with a chill. The fever Avhich follows immediately after the chill 
reaches the fastigiiim (104° to 106° F.) usually within twenty-four 
hours, remains high for five to seven days, and falls by crisis. There is 
an afebrile intermission of five to seven days, then the fever is repeated.^ 
Convalescence usually begins at the close of the second paroxysm; 
it may not occur until the close of the third or even fourth paroxysm. 
The incubation period is from two to fourteen days. The mortality 
is low, less than 4 per cent of all cases. The spleen is enlarged, there 
is profuse sweating, frequently jaundice, and occasionally diarrhea. 
Morphology.— The organism is spiral in outline and of moderate 
size. Schellack- states that the average diameter is 0.4 micron; the 
length varies from 15 to 20 microns. Other investigators give as 
measurements, diameter 0.25 micron, length from 7 to 10 microns. 
The discrepancy appears to be attributable to the fact that younger 
organisms are about 10 microns in length, the older forms being much 
longer. There are from 20 to 40 spirals in each individual cell, the 
number depending upon its length. Very frequently the ends are 
tapered. Fresh preparations viewed by dark-field illumination 
exhibit three distinct types of motion; a rotation around the long 
axis, which causes the organism to move rapidly through the medium 
in which it is suspended, an undulatory movement, and a lateral 
movement in all planes. The motility is caused by the rhythmic 
contractions of a terminal flagellum, according to Novy and Knapp.^ 
Zettnow^ believes the organism possesses peritrichic flagella. This 
has not been confirmed. Reproduction takes place typically by longi- 
tudinal fission according to Noguchi.* Less commonly he has observed 
transverse fission. 
Isolation and Culture.— The organism appears in the blood stream 
only during the pyrexia. Novy and Knapp** observed multiplication 
of Spironema recurrentis in defibrinated rat's blood and succeeded 
in keeping these organisms alive on blood agar for forty days, at the 
end of which time they were still infective for rats. No actual mul- 
tiplication, however, was observed in this medium. Noguchi^ has 
gro^\Tl the organisms in pure culture, using the method described 
previously (see Treponema pallidum). The organisms develop with 
considerable rapidity, a distinct clouding of the medium being observed 
after twenty-four to forty-eight hours' incubation at 37° C. The 
maxinuun growth is reached at the end of a week. 
Pathogenesis. — .l7n?/;a/. — Pure cultures retain their original virulence 
for rats and mice for several transfers in the agar ascitic fiuid tissue 
medium described by Noguchi. The lesions produced in experimental 
animals are essentially the same as those observed in man. The disease 
can be transmitted by inoculation from man to monkeys, from monkey 
' Obermeier loc. cit. 
2 Arb. a. d. kais. Gesamte, 1908, 27, .364. 
3 Jour. Infec. Dis., 1906, 3, 291. ^ Deutsch. med. Wchnschr., 1906, 32, 376. 
!■ Jour. Exp. Med., 1912, 16, 207. « Jour. Am. Med. Assn., 1906, 47, 2152. 
7 Loc. cit., p. 208. 
38 
