2 Gen. Sub. 
I. GENERAL SUBJECTS. 
bridge Natural History (309). Ernest Thompson’s “Wild Animals I have 
known” (759) touches the high-water mark of popular natural history. 
Very striking general essays are those in Brooks’ “Foundations of 
Zoology” (89); and the discussion of the relations of biology to other 
departments of thought by Mackintosh (491) is also important. Zittel’s 
history of geology and palieontology (856) is the most noteworthy historical 
contribution. 
Concerning distribution, we may especially mention the works of 
Kirchhoff (400), Scharff (686), W. L. and P. L. Sclater (709). 
Pruvot’s essay (628) on freshwater conditions is a welcome summary of 
hitherto scattered facts. 
Driesch’s criticism of morphological methods (180), Metchnikoff’s 
essay on senile degeneration (531), the second volume of Davenport’s 
experimental morphology (155), Beard’s short paper on the thymus (47), 
Cuenot’s research on excretion in Molluscs (142), Green’s text-book on 
fermentation (288), Loeb’s introduction to comparative psychology (468), 
and Whitman’s essay on “Animal Behaviour” (832), seem to the recorder 
to be outstanding representatives of the work noted in sections 3 and 4 of 
the Subject-Index. 
Regarding protoplasm and the cell, we may note the studies on plasmic 
structure by His (352), Heidenhain (322a), and E. B. Wilson (838-841), 
H^ecker’s useful course of practical lessons (300), Fischer’s criticism of 
technique and theory in modern cytology (233), and Rhumbler's analysis 
of cellular processes (656). 
The section on germ-cells includes studies on ovum-structure by 
Flemming (239) and Wilson (840), Morgan’s experiments on the action 
of salt-solutions (552), Loeb’s remarkable experiments on the supposed 
artificially induced parthenogenesis of sea-urchin ova (466), Vernon’s 
observations of the effects of staleness (790), Delage’s revelation of the 
possibilities of merogonic fertilisation (163-165), and several important 
discussions on maturation, e.g. by H^ecker (301), Strasburger (746), 
and Guignard (297). 
In embryology the analytic work of Driesch (183), the summaries by 
Mehnert (522 & 523), the discussions on recapitulation, e.g. by Rabl (635), 
on cell-lineage, e.g. by Wilson (839), and on germinal layers, e.g. by 
Del age (166), may be taken as characteristic of 1899, as of several 
previous years. 
Researches on experimental embryology, less numerous than in recent 
years, are well represented by those of Delage (163-165), Fere (223-226), 
O. Hertwig (343), Schultze (701, 705). 
Concerning sex and reproduction, papers abound; we would especially 
point out Ewart’s Penycuik Experiments (213), Rorig’s study of the 
correlations between gonads and antlers (664 & 665), Loeb’s experiments 
(466), and Conklin’s observations on sexual dimorphism in Crepidula 
(134). The literature on regenerative processes is conspicuously abundant, 
among the most important contributions being those of Weismann (821 & 
822), Morgan (549), Bordage (71—75), Przibram (629) and Herbst (329). 
Apart from discussions and expositions, the contributions to the study 
of heredity are not numerous ; we note those of Galton on a measure of 
the intensity of hereditary transmission (261), Ewart (214 & 215) on 
reversion and telegony, Pearson (598) on the inheritance of fertility and 
fecundity, Warren (812) on inheritance in parthenogenesis. 
The general problems of organic evolution are discussed by Brooks (89), 
Jordan (380), Hutton (367), Le Dantec (436), and many others. 
Probably more important are a few contributions towards the statistical 
study of variation, e.g. by Davenport (156), Duncker (189-191), Kyle 
(420), and the illustrations of selection supplied by Beeton & Pearson 
(54) and Bumpus (95). 
