1869.] Zoology. 153 



the others thus developed in the individual necessarily arise in 

 societies of men, and are naturally selected, being a source of strength 

 to the community which has them most developed : and there is no 

 excuse for speaking of a failure of Darwin's law or of " supernatural " 

 selection. We must remember what Alfred Wallace has insisted 

 upon most rightly — that in man, development does not affect so 

 much the bodily as the mental characteristics ; the brain in him has 

 become much more sensitive to the operation of selection than the 

 body, and hence is almost its sole subject. At the same time it is 

 clear that the struggle between man and man is going on to a much 

 larger extent than the writer in 'Fraser' allowed. The rich fool 

 dissipates his fortune and becomes poor ; the large-brained artizan 

 does frequently rise to wealth and position ; and it is a well-known 

 law that the poor do not succeed in rearing so large a contribution 

 to the new generation as do the richer. Hence we have a perpetual 

 survival of the fittest. In the most barbarous conditions of man- 

 kind, the struggle is almost entirely between individuals : in pro- 

 portion as civilization has increased among men, it is easy to trace 

 the transference of a great part of the struggle httle by Httle from 

 individuals to tribes, nationSj leagues, guilds, corporations, societies, 

 and other such combinations, and accompanying this transference 

 has been undeniably the development of the moral qualities and of 

 social virtues. 



Morphology. 



Tlie Early Stages of Development in Vertebrates. — Dr. Wilhelm 

 His, professor at Basel, and a worthy pupil of the great pioneers of 

 embryology, Eathke and Von Bar, has recently pubhshed a valua- 

 able work on the above subject, illustrated with twelve plates. The 

 principal point upon which Dr. His insists is the presence of two 

 germinal elements — the principal or primary germ, and the sub- 

 ordinate or secondary germ. From the first proceed the most 

 essential tissues, viz. the nervous, muscular, and epithehal, whilst 

 from the second arise the skeletal and nutrient structures, viz. con- 

 nective tissues, cartilage, bone, and the vascular system. Dr. His 

 traces out fully the development of each of these two portions, which 

 he distinguishes in the early embryo, and describes how they grow 

 the one into the other, eventually producing a most complex inter- 

 lacement of parts. He also points out that the development of the 

 secondary germ is very much afiected by mechanical conditions, and 

 endeavours to show how the form and relation of parts is thus 

 brought about in the embryo. The perivascular lymph-spaces of 

 the brain discovered by Dr. His are shown to arise from the intru- 

 sion of blood-vessels formed by the secondary germ into spaces 



