ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 171 



Surgery, Zoology, Botany, and so on, throughout the nineteenth century. 

 Although the book is heavy, the contents are not ; and the author de- 

 serves congratulation on his achievement. He has succeeded in avoiding 

 platitudinarian vagueness on the one hand and mere cataloguing on the 

 other, and his work should find a place in the libraries of those interested 

 in the historical development of the science of biology and the art of 

 medicine. Most of the portraits, which include Virchow, Darwin, 

 Pasteur, Haeckel, Lister, Koch, Sachs, are very successful. 



Present Position of the Theory of Descent.* — Prof. H. E. Ziegler 

 has made a separate publication of his lecture on this subject to the 

 1901 meeting of the German naturalists and physicians. All that 

 Ziegler says is worth reading, and the lecture has appended to it biblio- 

 graphic notes and appendices on Natural Selection, Neovitalism, Brain 

 and Mind, &c. 



Aid to the Study of Zoology, f — G. P. Mudge has written an intro- 

 duction to the study of zoology on what may be called the comparative 

 anatomy method. After an introduction on the scope of biology and 

 the characters of the great phyla, he discusses (a) the comparative 

 morphology of Vertebrates, illustrated by Ampluoxus, dogfish, frog, and 

 rabbit ; (b) the same for Invertebrates, illustrated by crayfish, cockroach, 

 fresh-water mussel, and earthworm ; (c) the structure of Hydra, illus- 

 trating diploblastic non-coelomate animals ; (d) Paramoecium and Amoeba, 

 illustrating the Protozoa. Then follow chapters — with more individu- 

 ality—on development and reproduction, heredity, and variation. The 

 book is a model of terseness, and, while we do not think that it can be 

 fairly called a " Text-book of Zoology," it is an accurate and informa- 

 tive introduction to comparative morphology and to certain aspects of 

 Biology. 



Immunity.^ — Prof. Elie Metchnikoff published in 1883 a now well- 

 known work on the comparative physiology of inflammation, in which he 

 emphasised the importance of the phagocytes. He has now given us a 

 similar treatise on immuoity against infectious diseases, in which he 

 maintains, against the conclusions of many other investigators, that the 

 theory of phagocytosis is indispensable in the interpretation of im- 

 munity. 



Statistical Study of Organisms.§ — Prof. L. Cameranohas previously 

 discussed || the determination of indices of variability, variation, fre- 

 quency, &c. ; and he deals in the present communication with the index 

 of the absence of a given character, the index of correlation, and the 

 index of asymmetry. We cannot summarise the paper, but the reference 

 may be useful to those interested in statistical study. 



Animals in Hot Water.U— E. Issel has studied the fauna of hot 

 springs and pools in Italy, and gives a list of 110 species. Many flourish 



* Jena, 8vo. See Anat. Anzeig., xx. (1902) p. 544. 



t A Text-book of Zoology, London, 1901, 8vo, viii. and 41G pp., 100 figs., and 

 1 col. pis. 



+ L'inmiunite' dans les maladies infectieuses, Paris, 1901, 8vo, 43 coloured figs. 

 See Journ. Anat. Phvsiol. norm, path., xxxviii. (1902) p. 104. 



S Atti Ace. Sci. Torino, xxxvi. (1901) pp. 371-6. || Op. cit., xxxv. (1900). 



% Boll. Mus. Zool. Genova, No. 100 (1900) pp. 1-4; No. 106 (1901) pp. 1-15 

 (2 pis. and 4 figs.). See Zool. Centralbl., ix. (1902) pp. 38-9. 



