84 Scientific Intelligence. 



The cooperation of the group of widely known experts repre- 

 sented in the authorship of this work has produced an authorita- 

 tive monograph of the greatest importance to the science of 

 entomology. For, in spite of the fact that this order of insects in- 

 cludes some of our most destructive pests as well as many of the 

 most beneficial forms, it has hitherto been impossible for even the 

 trained entomologist to identify many of the species. This report 

 now makes the identification of genus and species possible to the 

 general student of insects. The publication of such a volume as 

 this should be a source of much gratification not only to the 

 authors and to other entomologists but to the citizens of the State 

 under whose auspices it has appeared. w. r. c. 



6. The Biology of Twins (Mammals); by Horatio Hackett 

 Newman. Pp. xiv, 185. Chicago, 1917 (University of Chicago 

 Press). — The writer bases his discussion of this interesting sub- 

 ject on his own researches on the process of twinning in arma- 

 dillos. He presents evidence to support the generally accepted 

 view that twirls in sheep, cattle and man are sometimes produced 

 by the fertilization of two distinct eggs, while in other cases they 

 may result from the division of a single Qg^g or embryo. The 

 latter are the so-called identical twins. The conditions found in 

 twins help to elucidate some of the important biological problems 

 connected with heredity, sex, and general development. 



w. R. c. 



7. l^ie Tkeovij of Evolution, unth Special Reference to the 

 Evidence upon which it is Founded; by William Berryman 

 Scott. Pp. xiv, 183. New York, 191.7 (The Macmillan Com- 

 pany). — This volume consists of six lectures designed for presenta- 

 tion before a popular audience. The principal evolutionary doc- 

 trines are explained and as critically examined as the brief course 

 of lectures will permit. The evidences of evolution as supported 

 by com))arative anatomy, embryology, blood tests, paleontology, 

 geographical distribution and experimental work are logically 

 presented and in sufficient detail to give the general reader a good 

 idea of what the theory of evolution stands for at the present 

 time. w. R. c. 



8. A Chemical Sign of Life ; by Shiro Tashiro. Pp. ix, 

 142. Chicago, 1917 (University of Chicago Press). — In this 

 little volume the author discusses irritability as a sign of life, 

 and explains the relation between irritability and metabolism 

 resulting in the production of carbon dioxide. By means of an 

 ingenious apparatus sufficiently small quantities of this gas can be 

 detected to determine whether a single seed, a nerve fiber, or any 

 plant or animal tissue, still possesses the irritability characteristic 

 of life. Hence the test for life is the capability of c irbon dioxide 

 formation, and the quantity of life present can be measured by 

 the relative amount of this gas produced in a given time. The 

 "biometer," by means of which these tests are made, is fully 

 described in an appendix. w. r. c. 



