ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 22^ 
temperatures ( - 70° to — 110° C. for 36 hours). The mycele continues to 
develop, though much more slowly than at ordinary temperatures, and 
normal sporanges are formed. Since respiration is entirely suspended at 
this temperature, the ordinary theory that respiration is a necessary 
condition of vegetable life must be abandoned. 
Protoplasm of Mortierella.* * * § — M. L. Matruchot states that in a 
species of this genus of Fungi the older parts of the hyphse contain no 
protoplasm ; or, if there is any, it is granular, without structure, and 
encloses drops of oil. In the younger parts, on the other hand, the 
cytoplasm consists of a hyaline portion, not sensitive to staining reagents, 
penetrated by filaments which are only slightly granular, and which 
take up stains readily. These threads vary in number from 2 to 10, 
but do not constitute a network. They vary considerably in thickness, 
and are the seat of the streaming of the protoplasm, which does not tako 
place in the denser surrounding hyaloplasm. 
Characters of Ustilagineae.t — Herr P. Dietel describes the characters 
of Ustilago IscJisemi, parasitic on Andropogon Ischsemum. It possesses 
two kinds of hyphae : — the peripheral, which arise in a somewhat thick 
layer immediately beneath the epiderm of the host-plant, and develop 
into colourless sterile epidermal cells ; and the fertile, which run at right 
angles to the former, produce the ustilagospores by successive abstric- 
tions, and exhaust themselves in the formation of them. The species 
must belong to the genus Cintractia , if the centripetal order of formation 
of the spores can be retained as a distinctive generic character. But 
the author shows that it cannot be so retained. Other species of TJstilago 
exhibit the same differentiation of hyphse into the envelope-producing 
and the spore-producing kinds. A similar basipetal formation of clusters 
of spores occurs in Tolyposporium Junci. 
Composition of the Mycele of Mould-Fungi. :J — Herr Marschall has 
investigated the composition of the mycele of typical mould-fungi — 
Aspergillus niger, Penicilliim glaucum , Mucor stolonifer— and finds the 
average percentage of proteid substances to be as high as 38, while of 
cellulose there is only 5*03 per cent., and of substances soluble in 
alcohol 14*03 per cent. As regards their composition, mould-fungi 
occupy an intermediate position between bacteria and the higher plants, 
containing more nitrogenous matter and less carbohydrates than the 
latter, more carbohydrates and less nitrogenous matter than the former. 
As contrasted with the spores of Penicillium glaucum , the mycele contains- 
a larger proportion of proteids, while the spores contain nearly twice as 
much cellulose, starch, and substances soluble in alcohol. 
Histology of the Uredineae.§ — M. Sappin-Trouffy has again followed' 
out carefully the history of development of the Uredinese in the following 
genera : — Uromyces, Puccinia , Gymnosporangium, Triphragmium, Phragmi- 
dium, Melampsora , Thecopsora, Cronartium , Endophyllum, Coleosporium y 
* Comptes Rendus, cxxiii. (1896) pp. 1321-3. 
t Flora, lxxxiii. (1897) pp. 77-87 (1 pi.). 
X Arch. f. Hygiene, xxviii. (1896) p. 16. See Bot. Centialbl., 1896, Beili., p. 483. 
§ Le Botaniste (Dangeard), v. (1896) pp. 59-244 (70 figs.''. Cf. this Journal, 
1893, p. 342. 
