350 



SCIENCE 



[Vol. LV, No. 1422 



ments^ carried out with a much more massive 

 screen (9603 Kg. lead instead of 104 Kg. 

 mereurj') apparently finds an absorption co- 

 efficient of only one-third the value given, by 

 his earlier experiments. The actual difference 

 in weight found was only 0.002 milligram. In 

 view of the extremely small quantity to be 

 detected and the large amount of evidence 

 against the existence of such an effect, it may 

 be fairly assumed that Majorana's result is in 

 error. 



Paul R. Hetl 



BUKEAU OP StANDAKDE 



Washington, D. C. 



SCIENTIFIC BOOKS 



A Study of Some Social Beetles in British 

 Guiana and of their Relations to the Ant- 

 2}lant Tachigalia Wm. M. Wheeler. 

 Zoologica, Dec. 24, 1921. 

 Five Years' Observations (1914-1918) on the 

 Bionomics of Southern Nigerian Insects, 

 chiefly directed to the Investigation of Lycce- 

 nid Life-histories and to the Relation of 

 Lyccenidce, Diptera and other Insects to Ants. 

 Charles 0. Farquharson. Trans. Entomo- 

 logical Society'- of London, 1921. (Published 

 Januarjr, 1922). 



These are many excellent reasons for the 

 study of insects. They constitute the majority 

 of living animals, so far as at present known; 

 and in their relations to one another and to the 

 environment present biological complexes the 

 analysis of which tests the powers of the keen- 

 est observers. We go to the Protozoa to find 

 the problems of heredity and environment re- 

 duced to the simplest terms ; but we turn to the 

 world of insects to learn what life can do in 

 developing the most intricate, diverse, and 

 many-sided adaptive mechanisms and habits. 

 It may be said that the most elaborate poem 

 consists of nothing but letters of the alphabet, 

 and in the same sense all the phenomena of 

 insect life are implied in the simpler reactions 

 of unicellular animals. But after all, the poem 

 is very much more than letters or words, and 

 the biologist who tries to express the master- 

 pieces of vital activity in terms of simple and 

 '^Comptes Bendus, 173: 478, 1921. 



universal reactions can only do so by shutting 

 his eyes to the real nature of the phenomena. 

 It is, in fact, necessary to look in two directions 

 at once; to be equally alert to detect general 

 laws or principles, and to perceive special 

 cases, which in a real and significant sense are 

 unique. 



Not only do the insects thus illustrate the 

 wonders of life, but they afford us excellent 

 material for evolutionary studies, whereby we 

 may eventually understand in some measure 

 how the most complex structures and reactions 

 arose. They do this because the species are so 

 excessively numerous, and there is every reason 

 to suppose that much of their evolution has 

 been lateral; that is, by the development of 

 segregates without the disappearance of the 

 original stock. Thus it may v/ell happen that 

 a sufficiently extensive collection will show a 

 series of forms, along with their prototypes, 

 the latter still existing imder the original con- 

 ditions. Recent studies have revealed the exist- 

 ence of many slightly divergent races or species, 

 more or less different in their adaptations and 

 reactions, exposing the very mechanism of 

 evolution to our view. These phenomena, read 

 in the light of the remarkable genetic studies on 

 Drosophila and other insects, begin to acquire 

 extraordinary significance and interest. It 

 must further be said, that if we are to take 

 full advantage of the wealth of biological op- 

 portunity afforded by the insects, we must tui-n 

 to the tropics, where the number and divei-sity 

 of species is at a maximum. In the tropics 

 essentially similar climatic conditions have per- 

 sisted for ages, permitting the development of 

 biocoenoses which may be compared with old 

 and highly diversified civilizations. But the 

 detection and analysis of these requires resident 

 study or permanent stations, as the English 

 naturalist, A. R. Wallace, long ago insisted. 

 Expeditions, traveling rapidly over the coun- 

 try, appear more adventurous or romantic, and 

 often return with very large collections; but 

 any one who has occasion to study the speci- 

 mens so collected, must keenly realize the lack 

 of biological information. 



For all these reasons, the Tropical Research 

 Station in British Guiana, established by Mr. 



