1884.] 



MICROSCOPICAL JOURNAL. 



145 



I have recently discovered Xanthi- 

 dum antilopceum^ Arthrodesm7is In- 

 cus^ Staurasturn Sebaldi^ Cosmari- 

 um Pseudonittdulu7n^ and a few very 

 rare forms in a sunken pool. 



In conclusion, I often regret that 

 there are so many microscopists who 

 neglect this useful, healthful, and fas- 

 cinating branch of study. Do any 

 of the American microscopists keep 

 aquaria .'' I have kept aquaria of one 

 kind or another for over twenty years, 

 but only the last four years for the mi- 

 croscope, and have tried Vallisneria^ 

 Anacharis^ Nitella^ Char a vulga- 

 ris. For breeding rotifers, and for 

 harboring them, nothing, I find, comes 

 up to Chara vulgaris. The tube- 

 dwelling rotifers love to build their 

 habitations in the axils of the whorls 

 and in close proximity to the beauti- 

 ful red bunches of fruit ; this plant is 

 better even for this purpose than Ni- 

 tella^ and that is also very good. I 

 have at present about twenty tolera- 

 bly large aquaria in my room, all 

 with Nitella and Chara in abund- 

 ance, and fairly covered with Meli- 

 certa ringens and M. tyro., Stepha- 

 noceros., and many others too numer- 

 ous to mention here. 



E. H. Wagstaff. 

 Birmingham, England. 



Dr. Koch's Studies of Cholera. 



Though I live on the other side of 

 the world, I am a subscriber to and 

 constant reader of your Journal ; 

 and as I see you frequently refer in 

 your pages to bacteria and bacterial 

 pathology, I have sent you by this 

 mail a copy of one of our local pa- 

 pers, which contains two articles on 

 Professor Koch's recent discovery of 

 the bacillus associated with cholera. 

 As you are doubtless aware, he was 

 sent out by the German government, 

 with two other savants, on a commis- 

 sion to investigate the causes, etc., of 

 cholera. He went, in the first in- 

 stance, to Egypt, where he discov- 

 ered the specific bacillus, but only in 

 the human body and in the dejecta of 



the disease. From Egypt the com- 

 missioners came on — I rather think 

 at Professor Koch's own suggestion — 

 to India. In Calcutta he for the first 

 time discovered the bacillus in a tank 

 in the neighborhood of which cholera 

 of a virulent type was actually rag- 

 ing. If you could get the perusal of 

 the May number of the Indian Med- 

 ical Gazette., you will find the trans- 

 lation it contains of Professor Koch's 

 sixth report to his government very 

 interesting. 



There are two or three points in 

 connection with the articles in the 

 Indian Daily News that to me seem 

 to call for attention : One is the sug- 

 gestion to use acidulated enemata in 

 the early stages of the disease ; an- 

 other, the view that the bacillus 

 may set up a process allied to fer- 

 mentation, and thus convert the fluids 

 of the intestine into a specific poison ; 

 and finally, the hypothesis that the 

 bacillus of cholera does not enter the 

 human system by the mouth or the 

 nostrils, but gains admission from the 

 other extremity of the alimentary ca- 

 nal. To specialists these hypotheses 

 would probably suggest experiments 

 which might result in the discovery 

 of facts that would give us a better 

 control over cholera than we now 

 possess. Your position as Editor of 

 the American Monthly Micro- 

 scopical Journal, and the wide 

 circulation of your magazine, induce 

 me to call attention to matters which 

 in these days of bacterial pathology 

 may possess some interest for your 

 readers, and to send you the Indian 

 Daily News by this mail. 



W. J. Simmons. 

 Calcutta, May 28th, 1884. 



o 



The Selection and Use of Micro- 

 scopical Apparatus. 



[continued.] 



This was at once obvious upon the 

 consideration that the finest images 

 seen are got by viewing objects, as it 

 were, in the image of the source of 

 light. All critical images of transpa- 

 rent objects viewed by direct transmit- 



