ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 473 



or by some mechanical agent such as wind. The most favourable time 

 for germination is December, and the leaves may bo fresh and green and 

 still on the tree, or they may lie withering on the ground. 



He discusses at great length the germination and sexuality of the 

 spores, and gives the results of his experiments with the spores of 

 Goprinus and other Hymenomycetes. The paper is enriched by coloured 

 plates of the germinating spores and by many figures in the text. 



Predisposition and Immunity in Plants.* — Marshall Ward dis- 

 cusses this question in the light of his experience gained in the culture 

 of Eusts on Brome grasses. He rehearses the present position of our 

 knowledge of Uredineae, which as yet is one of great perplexity, and he 

 then gives a series of tables which record the results of his experi- 

 ments in infection. He was dealing with only one form of Eust, the 

 uredcspores of Puccinia dispersa. The results led to the conclusion 

 that the source from which the spores are taken and the specific pecu- 

 liarities of the grass inoculated have both to be taken into account if 

 infection was to be successful. Certain Bromes were readily infected 

 by spores taken from individuals of the same species, but were immune 

 to those of other Bromes in an increasing degree as the species was 

 further removed systematically. It was not easy to inoculate from one 

 specific group to another. The author made a careful examination of 

 the grasses to determine where the difference lay. The number and 

 size of the stomata and hairs were calculated, the thickness of the 

 leaves, &c. He came to the conclusion that the capacity for infection 

 is independent of the anatomical structure. The reason must be found 

 in some unknown biological distinction. 



Technical Mycology.t — Franz Lafar has published a second instal- 

 ment of his great work. The first volume dealt with Bacteria. The 

 newly issued part, which is to form the first third-part of the second 

 volume, deals with the general Morphology and Physiology of fungi. 

 Under Morphology he gives only the data necessary to the understanding 

 of the succeeding chapters. Special attention is devoted to the work 

 on Physiology and Biology that has been done within the last ten years 

 on fungi : as for instance, the chemistrv of the cell-wall, the necessity 

 for mineral food, the reaction to light, &c. A chapter is devoted to the 

 fermentation process induced by Zygomycetes, with an account of the 

 Mucorini. A necessarily large amount of attention is devoted to the 

 yeasts, especially to the Saccharomycetes ; to the form and chemistry of 

 the yeast-cell ; the morphology and development of yeasts ; the anatomy 

 and chemistry of the cells; their nourishment and reproduction, and 

 finally their requirement of organic and inorganic material, and their 

 need of oxygen. Emil Chr. Hansen writes a preface to the work. The 

 part is illustrated by 68 figures in the text and one plate. 



Schizophyta. 



Structure and Affinities of the Schizophyta. J — J. Massart has taken 

 up again the question of the presence of a nucleus in the Bacteria and 



* Proc. Camb. Phil. Soc, xi. (1902) pp. 307-28. 



t Technische Mykologie, ii., Jena (tfustav Fischer) 1901. See Centralbl. Bakt.. 

 viii. (1902) pp. 64S-9. 



% Eecueil de l'Inat. Bot. Univ. de Bruxelles, v. (1902) pp. 251-82. 

 August 20th, 1902 2 i 



