BACILLUS PYOGENES FCETIDUS. 375 



tative changes in bread, forming there fluid substances with a 

 disagreeable smell (similar to that of a mixture of peppermint 

 and turpentine oil), and the result of their growth is that the 

 bread becomes greasy in its interior and unfit for use. If the 

 yeast is washed with a half per cent, solution of hydrochloric 

 acid, the hurtful action of the organism seems to be prevented. 

 As to the production of gluconic acid, acetic acid, propionic 

 acid, &c., from carbo-hydrates as the result of the growth of 

 bacteria, see the chapter 011 " Fermentation." 



Bacilli which are able to split up the albuminous Putrefactive 

 molecule with the development of gaseous foul-smelling 

 products, and thus set up putrefactive fermentation of a 

 more or less intense character, are apparently very 

 common. Among the bacteria already described, and 

 which chiefly act in this manner, may be mentioned 

 bacillus butyricus, bacillus prodigiosus, bacillus fluores- 

 cens putidus, bacillus fluorescens liquefaciens, and a 

 bacillus isolated by Miller* from the intestines, but not 

 as yet more accurately described, and which furnishes 

 sulphuretted hydrogen and ammonia; also the bacillus 

 ureae, to be mentioned below; all these organisms are 

 able to split up albumen or gelatine, with the formation 

 of foul-smelling products. The following may also be 

 mentioned as having considerable power in this respect. 



Bacillus pyogenes fostidus (Passet) . 



This organism was obtained by Passet from the foul- Passet'sputre- 

 smeliing pus of an abscess. It consists of short rods, 

 rounded at the ends, with slow movements, 1*45 /*. in 

 length, and '58 p. in breadth, and frequently arranged in 

 pairs or in groups. One or two unstained spots can at 

 times be seen in the interior of the rods ; these are pro- 

 bably spores. In gelatine plates white points appear 

 after 24 hours, which develop at the surface in the form 

 of greyish-white patches, extending to about 1 cm. in 

 diameter, and becoming confluent, thicker, and whitish 

 in the middle, thinner and greyish towards the margin. 

 In puncture cultivations only fine points appear along 

 the track of the needle, but on the surface a delicate 



* Miller, Deutsche med. Woch., 1885, Nr. 49. 



