ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
573 
that in the former, after 3 days, 5-6 mg. of N 2 0 3 were present ; in tlie 
latter, after 16 hours 4 mg., and after 40 hours 1 eg. In an anaerobic 
culture 16 hours old, 0*75 mg. nitrite was formed ; in another 16 hours 
old, 2 • 5 mg., and after 42 hours 4 • 5 mg. When bouillon was rendered 
strongly alkaline with Na 2 C0 3 , the quantity of acid formed in anaerobic 
cultures was found to exceed that of aerobic cultures. 
Toxicity and Virulence of Cholera Vibrios.* — For studying the 
relations between the toxicity and virulence of cholera vibrios, Freiherr 
von Dungern used (1) a culture, isolated from a cholera case from the 
last epidemic in East Prussia, the virulence of which may be expressed 
by saying that 1/8 loopful (1/4 mgrm.) of a 20 hours old agar culture 
killed a guinea-pig of 200 grm., and another (2) which had been continu- 
ously cultivated for eight years in the Institute, and which was originally 
obtained from Calcutta. The virulence of the latter was almost entirely 
lost, for when 10-20 mgrm. of the culture were injected into the peritoneal 
sac of a guinea-pig, almost all the organisms were killed off. The two 
cultures were made in exactly the same way, all the usual precautions 
were carefully observed ; and although the animals did not react exactly 
alike, yet it was clearly determined that the toxicity of the two cultures, 
so different in their virulence, was very much the same ; even injections 
into the blood stream led to the same result. 
./Etiology of Dysentery.! — In a preliminary communication on the 
results of the examination of 62 cases of acute dysentery, Prof. A. Celli 
and Dr. R. Fiocca state that amoebae, and especially Amoeba coli , cannot 
be the direct cause of this disease on the following grounds : — (1) There 
are cases of epidemic, endemic, and sporadic dysentery without any 
amoeba}. (2) By inoculating with dysenteric faeces, or with cultures con- 
taining amoebae and bacteria, an amoeba-free dysentery can be induced ; 
and if the amoebae be killed a dysentery can be excited by inoculating 
with the bacteria and their poisons. (3) Amoebae are found in quite 
healthy intestines (A. coli, guttula, oblonga, spinosa , diaphana , vermicularis, 
and reticularis ). (4) In dysenteric dejecta Bacterium coli commune is 
constantly found, ordinarily in company with a typhoid-like transition 
variety ; frequently with Streptococci and sometimes with a Proteus. 
(5) Dysentery may be artificially induced by means of B. coli com. or 
two other species, and it seems possible that the combined action of two 
or more organisms on the intestines, by altering the environment, converts 
B. coli com. into the variety Bad. coli dysenterise, which retains its spe- 
cific potentiality through a series of animals. This variety is distin- 
guished by excreting a toxin capable of setting up a typical dysentery. 
Immigration of Bacteria into Cysticerci4 — Though bacteria can- 
not penetrate the walls of the echinococcus bladder, they may, according 
to the observation of M. C. Frenkel, pass into Cysticercus pisciformis. 
A small quantity of a sterilised culture of Staphylococcus citreus was 
subcutaneously injected into a rabbit, and later on an attenuated culture 
* Zeitschr. f. Hygiene u. Infektionskrankheiten, xx. p. 147. See Centralbl. f. 
Bakteriol. u. Parasitenlc., l te Abt., xvii. (1895) pp. 893-4. 
t Centralbl. f. Bakteriol. u. Parasitenk., l te Abt., xvii. (1895) pp. 309-10. 
+ Compt. Rend. Soc. Biol., 1894, No. 30. See Centralbl. f. Bakteriol. u. Para- 
sitenk., l te Abt., xvii. (1895) p. 910. 
