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1908 Hartmann (M.). — Eine neue Dvsenterieamobe, Entamœba tetragena 
(Arch. f. Schiffs-u. Tropenhyg., V). 
1911 Liston (G.) et Martin (C. H.). — Contributions to the study of patho- 
genic amœbæ from Bombay (Quart. Journ. of Micr. sc., LVII). 
1904 Musgrave et Clegg. — Amebas : their cultivation and œtiologic si- 
gnificance ( Manila. Dept. of the Int. Bur. of Gov. Lab. ; Biol. Lah., 
XVIII). 
1907 Pinoy (E.). — Rôle des bactéries dans le développement de certains. 
myxomycètes (Ann. Inst. Past., L). 
1908 Walker (E. L.). — The parasitic Amebæ of the intestinal tract of man 
and other animais (Journ. of Med. Research, XVII). 
1911 Werner (H.). — Entamœba coli, in Handbuch der Pathogenen Proto- 
zoen. Leipzig Ambrosius Barth. 
1911 Williams (A.). — Pure cultures of^mebæ parasitic in Mammals (Journ. 
of Med. Res., XX). 
Réduction of virulence in a strain of 
Trypanosoma hippicum selected 
from a guinea pig* 
By S. T. DARLING. 
Laveran (i) lias shown that in the passage of Tr. Evansi (Try¬ 
panosome of Surra of Mauritius and the varietÿ Mbori) and of 
Tr. gambiense, through guinea pigs^ the virulence is increasecl, 
while for the trypanosome of Togo the virulence is diminished. In 
determining this point Laveran took the mean number of days in 
the different removes required to kill guinea pigs. 
In guinea pigs infected with Tr. hippicum I hâve observed 
that the duration of the disease lias ranged between 27 and 
336 days. Curiously, the extremes 27 and 336 are represented by 
two guinea pigs inoculated the sanie day from horse No. 121 (na- 
turally infected). 
This was a virulent strain, for several animais subinoculated 
from these guinea pigs died as a resuit of the infection. The gui¬ 
nea pig that survived 336 days had been inoculated from horse 
n° 121 Feb. 24, 1910. Forty-two days after inoculation (April 7) 
a dog was sub-inoculated from the guinea pig and the duration of 
the disease was 38 days. This would seem to be the usual duration 
(1) Laveran, Bull, de la Soc. Path. exot., 1908, vol. I, p. 198. 
