ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
197 
under unhealthy conditions, in order to elucidate its supposed connection 
with infective diseases. The general inference from their observations 
seems to be that when oysters are removed from their natural environ- 
ment they are more or less easily infected, and that clean and fresh sea- 
water is inimical to pathogenic organisms (_B. typhosus) The coli group 
of bacilli was frequently found in shell-fish as sold in towns, and 
especially in the oyster, and also an anaerobic spore-bearing bacillus 
having the characters of B. enter itidis sporogenes. 
The authors include in their research, work on the normal histology 
of the oyster, and on the vexed question of the greening of oysters. 
Greening may be due to a leucocytosis associated with the presence of a 
greatly increased amount of copper, or may depend upon the presence of 
a special pigment, “ marennin.” 
Leucocytes and Arsenic Intoxication.* — Dr. Besredka, in a first 
memoir on immunity to arsenic compounds, deals with the part played 
by leucocytes in the intoxication produced by trisulphide of arsenic. 
The injection of trisulphide solution into the peritoneal sac of guinea- 
pigs is immediately followed by hypoleucocytosis. The subsequent 
phenomena are determined by the amount of the poison. If the dose be 
a fatal one, there is negative chemiotaxis, and little or no phagocytosis ; 
while the survival of the animal is marked by positive chemiotaxis and 
by intense phagocytosis. The phagocytosis is not, however, merely con- 
fined to englobement and chemiotaxis, for the trisulphide is digested, 
and is transformed into a soluble compound which is excreted by the 
kidneys. 
Persistence of Bacteria in the Cow’s TJdder.f — Mr. A. B. Ward, in 
the course of experiments relative to the persistence of bacteria on the milk- 
ducts of the cow’s udder, found that the cistern could be temporarily 
Colonised with B. prodigiosus, for this microbe was detected in cultiva- 
tions from the milk for six days after. The author’s experiments also 
show that bacteria may exist in the udder for a considerable length of 
time, and that although they can usually be demonstrated in the milk, 
this may not always be the case. These observations support the view 
that the last drawn milk is not necessarily sterile. 
Importance of Intestinal Bacteria in Nutrition. :J — For his experi- 
ments as to the importance of intestinal bacteria in nutrition, Herr M. 
Schottelius made use of chickens hatched under sterile conditions. 
Though the idea is in itself perfectly simple, the details of the pro- 
cedure adopted were extremely complicated, and difficult to be carried 
out in practice. For these the original should be consulted. The ex- 
periments showed that fowls brought up under perfectly sterile conditions 
gained little in weight or size, the maximum increase in 12 days being 
only about 25 per cent. After 12 days there was, if anything, a decrease. 
Fowls brought up under ordinary conditions increase by the 12th day 
by 140 per cent., and by the 17th by 250 per cent. It therefore follows 
that in the case of chickens, at least, bacteria are very useful for diges- 
tive work. Cultivations made from the excrement proved devoid of 
* Ann. Inst. Pasteur, xiii. (1899) pp. 49-66. 
t Journ. Applied Microscopy, i. (1898) pp. 205-9 (1 fig.). 
X Arch. f. Hygiene, xxxiv. (1899). See Ann. Inst. Pasteur, xiii. (1899) pp. 77-80. 
