ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 883 



whicli it always presents the same phenomena, whether bred originally 

 in an extract of flesh of any degree of concentration, or an infusion 

 of hay, or whether cultivated in a breeding oven, or obtained direct 

 from the entrails of the fowl. No transformation into any other 

 bacterial form has been observed ; it presents the nearest resemblance 

 to the bacterium of the cattle disease. Its chief characteristics are 

 the much smaller elasticity of its cell-wall, the rapid liquefaction of 

 the jelly, and the formation of spores, at spots of which the cocci 

 are formed. No " spirally coiled masses of micrococci " have been 

 observed, as described by Koch in the case of other bacteria. 



Diastatic Ferment of Bacteria.* — Eecent investigations have 

 conclusively established the universal occurrence of diastatic ferments 

 in different parts of plants, and have thrown a new light on the pro- 

 cesses of nutrition and fermentation. 



According to ^earlier observations, the presence of diastase in the 

 plant was limited to germinating wheat or barley, and knowledge in 

 regard of its wider diffusion has been advanced by the recent works 

 of Gorup-Besanez, Will, Kranch, and especially Baranetzky. The 

 researches of Musculus, E. Schultze, O'Sullivan, and others, have 

 afforded an insight into the quantitative relations and the modifying 

 external factors of temperature and acidity concerned in the action of 

 diastase in the transformation of starch into glucose. 



Having in view the action of bacteria as causes of putrefaction or 

 fermentation in which the destruction of the putrescible or fermen- 

 tescible body is accomplished by the appropriation for the purpose of 

 nutrition by the bacteria of constituent nitrogen or carbon, the ques- 

 tion may be asked, Can bacteria also obtain their carbon from starch, 

 just as by the researches of Pasteur and Cohn they have been proved 

 to be capable of obtaining it, not only from sugar, but from ammonium 

 tartrate ? Are bacteria, by the secretion of a starch-transforming 

 ferment analogous to diastase, or in any other, but not clearly-defined 

 way, capable of transforming starch into soluble, diffusible, and 

 nutrient combinations ? Notwithstanding the numerous investiga- 

 tions into the chemical and physiological relations of bacteria, very 

 little has been made out in regard to their action on starch — a cir- 

 cumstance from which it may be presumed that the solution of starch 

 by bacteria can be effected only in certain instances. In his work, 

 ' Ueber die niederen Pilze,' Nageli refers to the secretion by these 

 organisms of a special energetic ferment capable of changing milk- 

 sugar into fermentescible sugar, starch and cellulose into glucose, 

 and of dissolving coagulated albumin and other albuminates, and 

 Sachsse alludes to the circumstance of starch solution undergoing no 

 change so long as it is protected from the influence of organic germs 

 by which otherwise it quickly undergoes transformation. 



J. Wortmann has made some experiments on the sul^ect, the 

 results of which are : — 



1. Bacteria are capable of acting on starch, whether in the 



* Zeitschr. Physiol. Chem., vi. (1883) pp. 287-329. See Jonrn. Chem. Soc. 

 Abstr., xliv. (1883) pp. 930-8. Cf. this Journal, ii. (1882) p. 829. 



