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SUMMARY OF CURRENT RESEARCHES RELATING TO 
ing action on the development of micro-organisms ; that direct sunlight 
possesses an effective sterilizing action on micro-organisms, and also 
retards their development ; that this sterilizing action is most powerful 
when the sun’s rays fall perpendicularly to the surface of the cultiva- 
tion ; that the sterilizing and inhibitory action varies, as to time, with 
different micro-organisms and with the cultivation medium ; cultivated 
in bouillon, anthrax-spores resist the action of light about equally or 
rather less than the bacilli ; that spores are killed by light, as spores 
and not as young bacilli ; that light retards, but does not prevent spore- 
formation ; that it modifies the production of pigment, usually diminish- 
ing the quantity, but sometimes the quality ; that it attenuates the 
virulence of anthrax. 
Morphology and Biology of Streptothrix Foersteri Cohn.* — Dr. 
G. Gasperini describes at some length his experiments with Streptothrix 
Foersteri , an organism first described by Cohn. It was originally found 
in the concretions of the inferior lacrymal canal, but was afterwards 
discovered to be quite an ordinary inhabitant of the air of dwelling- 
houses. 
After describing how it grows on various media the author discusses 
its evolution cycle. The microbe is practically aerobic, for though it 
will throw out filaments in the absence of oxygen, the presence of this 
gas is necessary for the development of spores. The temperature most 
adapted for its growth is between 30° and 37°. 
No sensible effect was found to be exerted either on the mycelium 
or spores by diffused light, while direct sunlight had either an inhibitive 
or pernicious action. It would seem also that S. Foersteri is best cultivated 
in alkaline or neutral media, which are rendered acid by its development ; 
it is able to live as a parasite on fungi, but does not appear to have 
much pathogenic action when injected into rabbits or guinea-pigs. Illus- 
trations are given to show the character of the growth in gelatin, &c., 
and the appearance of the micro-organism under high powers. Here it 
is represented as a septate mycele, the filaments of which frequently end 
in a chain of small cells (spores.) 
Phases in the Development of the Cholera Microbe.| — Mr. G. F. 
Dowdeswell describes at length, under the head of phases in the 
development of the cholera microbe, a series of forms which were 
obtained by cultivating in moist heat and observed directly under the 
Microscope. The forms in question are morphological varieties due 
chiefly to altered conditions of environment, and hence it is possible that 
this alteration affords an explanation of the absence of the characteristic 
commas in some cases of cholera. At any rate the author’s observations 
go far to confirm the opinions of Naegeli, expressed thirteen years ago ; 
these were to the effect that the shape of schizomycetes is only invariable 
for similar external conditions. 
The forms described by the author are depicted in an illustration 
accompanying his paper, and are drawn under magnifications of 800 to 
1500. The shapes vary from small globules to large globules, with or 
without vacuoles, from ovoid and bacillus-like to amoeboid masses of 
* Ann. de Micrographie, iv. (1890) pp. 449-74 (3 pis.). 
t T. c., pp. 529-44 (1 pi.). 
