ZOOLOaY AND BOTANY, MICROSCOPYj ETC. 603 



The formation of cocci indicates a regression to the nostoc form, 

 which is also met with in the history of development of Drilosiphon. 

 Eesting spores are formed here and there along with the cocci, from 

 1-1 • 8 yu, in diam. ; and these occur also in the bacterium and vibrio 

 forms, in very long threads occasionally two. 



The author concluded, as the result of experiments, that Lepto- 

 thrix muralis has no power of inducing fermentation or putrefaction. 

 The presence of free oxygen is absolutely necessary for its 

 growth. It is best cultivated in water containing traces of iron, lime, 

 and potash salts. It is probably capable of carrying on an inde- 

 pendent existence ; but the presence of vigorous tufts of moss is 

 apparently favourable to its growth. 



The micro-conditions of the three principal forms of Leptothrix 

 muralis, the leptothrix form with its hormogonia, the nostoc form, and 

 the gloeocapsa or palmella form, are morphologically altogether equi- 

 valent to true bacteria, but physiologically they are as widely 

 removed from them as any green plant from a non-chlorophyllaceous 

 saprophyte. 



Action of Oxygen on Low Organisms.* — F. Hoppe-Seyler has 

 constructed an apparatus for the purpose of testing the influence on 

 the development of the lowest forms of animal life of an abundant 

 or restricted supply of oxygen. He finds that in the presence of free 

 oxygen the only certainly demonstrable products of the decomposition 

 of fluids containing albuminous substances are carbonic acid, ammonia, 

 and water. If the fluid is saturated with oxygen, neither hydrogen 

 nor marsh-gas makes its appearance ; the ordinary products of decom- 

 position, ibdol and skatol, are not formed at all, leucin and tyrosin 

 only temporarily. Microscopic examination shows that when decom- 

 position takes place in the presence of abundant oxygen, the Schizo- 

 mycetes are formed in much greater quantities than when the supply 

 of oxygen is small. The Schizomycetes and Saccharomycetes behave 

 in just the same way, from a chemical point of view, as all other 

 vegetable organisms, when supplied with abundance of oxygen ; they 

 absorb oxygen, and give oflf carbonic acid, water, and ammonia, or 

 some nitrogenous substance nearly allied to it. In the absence of 

 oxygen all decomposing organisms display fermentation-phenomena ; 

 but while the Schizomycetes and Saccharomycetes can remain in this 

 condition for a considerable time, all other organisms perish I'apidly 

 in the absence of oxygon. Certain Schizomycetes can sustain the 

 absence of oxygen for a considerable time, especially the one or more 

 species which split up cellulose into C 0^, C H^, and H^ ; but the 

 author altogether disbelieves the theory that there are organisms 

 which can exist only in the absence of oxygen. 



Biology of the Myxomycetes.f — E. Stahl has made a long series 

 of experiments on the cause of the movements of the plasmodia of the 

 Myxornycetes, especially of ^fhalium septicum. By causing one end 



• Zeitsclir. f. Phyhiol. Cbemie, viii. (1884) p. 214. See Nuturfoischer, xvii 

 (1884) p. lie. 



t Hot ZfK-, xlii. (1884) pp. 145-5(5, 1C1-7C. 187-91. 



2 s 2 



