332 The " Comma-shaped Bacillus'' as a Cause of Cholera. [part i. 



[Since this memorandum was submitted I have observed that Dr. Koch states, 

 in his recent address on the subject, that after his return to Berlin he had 

 examined, amongst other things, the secretions of the mouth for comma-shaped 

 bacilli, but had found none ; and, further, that he had consulted persons of much 

 experience in bacterial researches as to whether they had ever seen such organisms, 

 and was told that they had not. It may be of assistance to future obser\'ers if I 

 give the dimensions of half-a-dozen comma-shaped bacilli, as found in each of the 

 following situations : (a) In the alvine discharges of three cholera-affected persons ; (6) in 

 the small intestine of a person who had died of the disease, and in whom they 

 existed almost to the exclusion of other organisms ; (c) in a cultivation of them 

 in agar-agar jelly ; and id) in the secretions of the mouth of three healthy 

 persons, ranging from four to fifty years of age. The measurements were made 

 (with the valuable assistance of Mr. Arthur E. Brown, B.Sc. Lond.) under a 

 magnifying power of 1,000 diameters, a Powell and Lealand's Jg^th of an inch oil- 

 immersion lens, with a wide angle condenser, being used.] The results appear in the 

 following table : — 



Length and Width (in Micro-millimetres*) of Comma-shaped Bacilli in Choleraic 

 Material and Secretions of the Mouth in health. 



There is no difficulty in putting this statement to the test; and to any one 

 acquainted with the methods ordinarily adopted for staining and mounting fungal 

 organisms of this character, no special directions need be given. The procedure 

 followed by me to demonstrate these " commas " in the saliva is precisely that 

 adopted for finding them in the dejections. A little saliva should be placed on a 

 cover-glass (preferably in the morning before the teeth are brushed), and allowed to 

 dry thoroughly, either spontaneously or aided by a gentle heat. The dry film thus 

 obtained should be floated for a minute or two with one or other of the ordinary 

 solutions of aniline dyes adopted for such purposes, such, for example, as fuchsine, 

 gentian-violet, or methylene blue. The cover should then be gently rinsed with 

 distilled water, and the film re-dried thoroughly. The preparation may now be 



* One Micro-millimetre (;u) — -001 millimetre [ = ir?T7T5"]* 



f S-sliaped comma bacilli. 



