176 



THE AMEKICAN MONTHLY 



[September, 



section, perhaps attached to the sec- 

 tion of biology, or possibly it will be 

 abolished entirely, which will permit 

 of the distribution of microscopical 

 papers among the sections in strict 

 accordance with the subjects upon 

 which they treat, 



o 



The Bacillus of Cholera. — 

 Much public interest has been aroused 

 in the results of Dr. Koch's observa- 

 tions upon the cause of cholera, but 

 we have been waiting to receive a 

 definite account of what Dr. Koch 

 has discovered, and what his conclu- 

 sions concerning the matter ai'e, be- 

 fore presenting the subject to our 

 readers in this place. Dr. Koch's ob- 

 sei"vations and conclusions are now 

 published to the world, and although 

 our space does not admit of a de- 

 tailed account of his observations, 

 we may briefly indicate their general 

 character, and refer the reader to the 

 Deutsch. Medizin. Wochenschrift 

 for more complete information. 



It appears that Dr. Koch has dis- 

 covered an organism in the intestines 

 of choleraic patients that he regards 

 as a bacillus, but possibly it will turn 

 out to be a spirillum, which, from its 

 peculiar shape, has been designated 

 as the comma bacillus. These ba- 

 cilli, as far as observations have ex- 

 tended, are invariably associated with 

 cholera. They are found within the 

 glands, but especially between the 

 epithelium and the basement mem- 

 brane, where, by their active growth, 

 they destroy the epithelium, and per- 

 haps in this way give rise to the dis- 

 ease ; or they may generate a specific 

 poison which causes the disease. 

 They are found most abundantly in 

 the lower part of the intestine, and 

 more or less abundant according to 

 the severity of the attack. The com- 

 ma bacillus is smaller than the bacil- 

 lus of tubercle, but thicker in pro- 

 portion and curved like a comma, 

 but occasionally it assumes a double 

 curve, like the letter s. This is es- 

 pecially the case in cultures, when 

 the bacilli grow in the shape of long. 



delicate spirals, closely resembling 

 the form of the spirochaete of relaps- 

 ing fever. It grows v^^ithin a consid- 

 erable range of temperature, and is 

 not killed by freezing. No resting 

 stage has yet been observed. While 

 ordinary bacilli form, spores on drying, 

 the comma bacillus is immediately 

 killed by desiccation. Hence it fol- 

 lows that the disease is not likely to 

 be disseminated by merchandise, but 

 only by persons — possibly it may be 

 cari'ied by the wind for short dis- 

 tances. 



The discovery of the bacillus af- 

 fords an aid in the diagnosis of the 

 disease, but no means has yet been 

 discovered to destroy it when it once 

 gains a foothold within the system. 



While writing upon this subject we 

 cannot omit a brief reference to an 

 article in the New Tork Medical 

 youriial of August 30th by Dr. John 

 Bartlett, in which the author presents 

 some bold speculations concerning 

 the progress of cholera, and com- 

 pares it with the advance of the army 

 worm. The comparisons he makes 

 are very forcible and telling. The 

 subject has been well thought out, 

 and no person who is interested in the 

 study of contagious diseases should 

 fail to read the article. The specula- 

 tions concerning the dissemination of 

 the cholera germs are scarcely in ac- 

 cord with our present knowledge of 

 the comma bacillus, particularly as 

 regards its inability to survive des- 

 iccation ; nevertheless, the article is 

 very suggestive, and affords sugges- 

 tions worthy of careful consideration. 

 o 



Filamentous Projections on 

 Diatoms. — In an article in the June 

 number oi the Jotirn. R. After. Soc. 

 Mr. J. Babcock, F. R. M. S., de- 

 scribes and figures certain filaments 

 projecting from the frustules which 

 cause movement of particles v^^hen 

 the frustules pass near them, with- 

 out apparent contact. Careful ob- 

 servation, hov^^ever, reveals the pres- 

 ence of the straight filaments, which 

 were observed on Stirirella bifrotis. 



