Pamphlets on Biology Volume 2406; Kofoid Collection (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ...no formation of gas has, under the same conditions, ever been observed in the case of the typhoid bacillus. This latter mode (c)f distinguishing between the B. coli communis and the typhoid bacillus I have reduced to the following extremely simple and handy form suitable for their rapid differentiation: --The organism under investigation is inoculated into a test tube containing ordinary gelatine peptone in a melted state, the latter is shaken to distribute the bacilli throughout the liquid, which is then allowed to solidify and maintained at the ordinary temperature (18--20 C.). The tube, if it contains the B. coli communis, will invariably, aftei12--48 hours, exhibit numerous conspicuous gas bubbles distributed through the solid medium, whilst no such bubbles make their appearance in similar tubes containing the typhoid bacillus. The test possibly depends upon the meat extract containing sufficient dextrose (derived from the post-mortem transformation of the glycogen iich has been affirmed more especially by Kraus and subsequently Karlinski. This point is obviously of the very highest importce from a practical hygienic point of view, as it-is with unsterile table water that we are in practice alone concerned, and the ration of vitality ascribed to the typhoid bacillus in such water by th these observers is of very limited extent--not more than seven The experiments of Kraus are so striking, and have attracted so ach attention, that I will give them in more detail in the following ble: --These results indicate, therefore, that, on introducing the typhoid cilli into the potable waters in question, which were almost turally sterile, the typhoid bacilli promptly disappeared as soon as 3 water bacteria had undergone extensive multiplication, which d taken pl