ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 97 



pectose, a compound of lime with a substance which is chemically 

 closely related to cellulose, and which together with cellulose composes 

 the cell-walls. 



A. van Delden finds that the removal of pectose is effected by 

 various micro-organisms, among which are the aerobic bacteria B. me- 

 sentericus, B. subtilis, and their allies, certain moulds, and especially an 

 anaerobic bacterium to which he gives the name of Granulobacter 

 pectinovorum, and the nearly related Granulobacter urocephalum. 



These organisms secrete a special enzyme " pectosinase," which 

 converts the pectose into pectine, and the pectine into various sugars, 

 which undergo fermentation with the production of H, C0 2 , and 

 butyric acid. 



Granulobacter pectinovorum is a long slender rod, which later be- 

 comes swollen at one end by an oval spore ; grown in dilute malt 

 extract anaerobically, it produces fermentation without the formation 

 of butyric acid ; with starch, inulin, mannite, erythrite and glycerin, 

 fermentation could not be produced ; with pepton and with dilute 

 broth or albumen as a source of nitrogen, fermentation occurred in 

 glucose, laevoluse, galactose, milk-sugar, and maltose, with a slight pro- 

 duction of butyric acid ; with ammonium salts as a source of nitrogen, 

 fermentation cannot be produced with any of these sugars ; proteids 

 and gelatin are peptonised. Cellulose is quite unaffected by this 

 organism, hence the flax fibre remains quite unchanged in the process 

 of " retting." 



Morphology and Biology of Bacillus Zopfii.* — Swellengrebel has 

 isolated this organism from milk ; he regards it as being associated 

 with putrefactive processes. It is a very motile rod 2 • 5 //. long with 

 numerous flagella ; stains by ordinary dyes and by the methods of 

 Gram and Claudius. He is satisfied that spores are formed, having 

 followed the phases of their development on agar plates. On gelatin 

 plates the colonies have opaque white centres, with radiating offshoots 

 of smaller transparent yellowish colonies. He never observed lique- 

 faction of the gelatin ; he only obtained a growth in a gelatin stab at 

 a temperature of 22° C. On agar he distinguishes two forms of colonies, 

 the one small, greyish white, with fine offshoots and surrounded by a 

 transparent zone, as is described by Lehman and Neumann ; the other 

 resembling this, but of a denser appearance. Growth in bouillon varies 

 according to the temperature ; at room temperature it forms a sediment, 

 the liquid is not clouded, and there is no pellicle ; at 26° C. a pellicle 

 is formed, but he never found the medium clouded ; the reaction is 

 alkaline ; growth is equally good at 30° C. On potato it forms a 

 greyish-white film. In milk it produces no coagulation and no change 

 in reaction. In glucose and lactose broths it grew well : after 5 davs 

 he noted acid-production in both, especially with glucose ; the broth 

 was clouded and had a foetid odour ; he never observed any production 

 of gas. The power to form indol is variable ; a 7 -day old culture at 

 26° C. in pepton solution (2 p.c.) gave a strong positive reaction. He 



* Ann. Inst. Pasteur, xviii. (1904) p. 712. 

 Feb. 15th, 1905 H 



