PRODUCTS OF VITAL ACTIVITY. 141 



Miquel has given special attention to the study of bacteria which 

 produce alkaline fermentation in urine, and in addition to the spe- 

 cies above mentioned has described the following : Urobacillus Pas- 

 teuri, Urobacillus Duclauxi, Urobacillus Freudenreichi, Urobacillus 

 Maddoxi, Urobacillus Schutzenbergi. 



Viscous fermentation. A special fermentation which occurs 

 sometimes in wines, and in the juices of bulbous roots containing 

 glucose, and in milk, is produced by various bacteria. One of these 

 is a micrococcus which has been described by Conn under the name 

 of Micrococcus lactis viscosus. The fermented juices become very 

 viscous, owing to the formation of a gum-like product resembling 

 dextrin; at the same time mannite and CO 2 are produced. The 

 gum-like substance, called viscose by Bechamp, is soluble in cold 

 water and is precipitated by alcohol. Guillebeau (1892) has de- 

 scribed a micrococcus and a bacillus which produce viscous fer- 

 mentation ID milk Micrococcus Freudenreichi and Bacillus Hessi. 

 A micrococcus producing viscous fermentation in milk has also 

 been described by Schmidt-Muhlheim, and a bacillus by Lomer. 

 Bacillus mesentericus vulgatus also produces a similar change in 

 milk. 



Marsh gas, CH 4 , is produced by the fermentation of cellulose, 

 through the action of microorganisms the exact characters of which 

 have not yet been determined. According to Tappeiner, there are 

 two different fermentations of cellulose. The first occurs in a neu- 

 tral one-per-cent flesh extract solution to which cotton or -paper pulp 

 has been added. The gases given off are CO 2 and CH 4 and small 

 quantities of H 2 S. The second fermentation occurs when an alkaline 

 solution of flesh extract containing cellulose in suspension is used. 

 The gases formed are CO 2 and H. In both cases small quantities of 

 aldehyde, isobutyric acid, and acetic acid are produced. 



Hydrosulpliuric acid, H 2 S. This gas is produced during the 

 growth of certain bacteria. The conditions governing its develop- 

 ment have been studied by Holschewnikoff, who experimented with 

 two species, one isolated by himself and one by Lindenborn. named 

 respectively Bacterium sulfureum and Proteus sulfureus. The first- 

 mentioned bacterium, when inoculated into eggs, produced within 

 three or four days an abundant quantity of H,S ; the other did not. 

 Upon raw r albumin both species produced but little, and on the yolk 

 of egg a considerable amount of this gas. Upon cooked egg the 

 action was the reverse. In peptone-bouillon the evolution of H 2 S 

 was abundant : in the absence of peptone, ven~ slight. 



Putrefactive fermentation. The putrefactive decomposition 

 of albuminous material of animal and vegetable origin is effected 

 by a great variety of microorganisms and gives rise to the forma- 



