582 



SCIENCE 



[N. S. Vol. XXVII. No. 693 



So far, then, as the author sets up preten- 

 sions to give us a philosophy of any kind, 

 his volume deserves only adverse criticism; 

 in fact, it would be beneath criticism in this 

 respect did it not exemplify a frequently re- 

 curring tendency on the part of many scien- 

 tists to construct their philosophy by gen- 

 eralizing from what is really evidence on only 

 one side. However, if we disregard the 

 author's philosophical pretensions, and con- 

 sider his volume as what it for the most 

 part really is, viz., a history of astronomical 

 discovery, written in a style unusually clear 

 and interesting and portraying facts which 

 will set the lay-reader to thinking, then only 

 praise is due him for his endeavor, and may 

 his reappearance in the two volumes on The 

 Mechanism of Life and The Social Mechan- 

 ism, which he announces, be an early one. 

 E. G. Spaulding 



The Sense of Touch in Mammals and Birds, 



with Especial Reference to PapUlary 



Ridges. By Walter Kidd, M.D., F.Z.S. 



London, Adam and Charles Black. 8vo, 



pp. 176; 164 illustrations. 



This work, although hardly of sufficiently 

 broad scope to justify its main title, since it 

 treats of only a very limited region, still con- 

 tributes much to our general knowlege of the 

 character of the skin which covers the ventral 

 chiridial surface. 



After a brief introductory chapter, in which 

 the author explains the general plan of the 

 work, and reviews the scientific literature al- 

 ready published upon this subject. Dr. Kidd 

 proceeds to the discussion, which he divides 

 into tljree parts, (I.) the macroscopical, (H.) 

 the microscopical and (IIL) the physiological 

 study of the volar and plantar skin. This 

 work comprises a study of 86 species of mam- 

 mals representing 59 genera and 9 orders; 

 also one species each of 11 genera of birds. 



The varieties of skin are classified some- 

 what arbitrarily as follows: leading types, (1) 

 smooth epidermis, (2) corrugated epidermis, 

 (3) scales, (4) nodules, (5) hair, (6) rods, 

 (7) papillary ridges; mixed types, (A) epi- 

 dermis more or less corrugated, with coarse 

 transverse ridges on he digits, (5) corrugated 



epidermis with papillary ridges, (C) nodules 

 with papillary ridges, (D) hair with coarse 

 transverse ridges and smooth pads. Prac- 

 tically no attempt is made, however, to 

 show any morphological relationship between 

 these various types, a phase of the investiga- 

 tion which would be of the greatest interest 

 and value. 



Careful descriptions are given of each spe- 

 cies studied, and the descriptions are accom- 

 panied by many diagrams. Especial atten- 

 tion is given to the occurrence of the papillary 

 ridged type of skin. This type the author 

 finds, as have other investigators, partly cov- 

 ering the volar and plantar surfaces of a few 

 of the marsupials, rodents and carnivores and 

 of all of the prosimians; but it is in the 

 primates that the development of this form 

 of skin becomes so complete and universal 

 that it is justly designated "a character of 

 ordinal rank." However, Dr. Elidd's state- 

 ment that " of course, its highest development 

 is found in the hand and foot of man," is 

 plainly refuted by his own excellent diagrams 

 showing the far more highly developed pat- 

 terns upon both the volar and plantar areas 

 of monkeys, particularly below the anthro- 

 poids. Indeed, one can but see in this state- 

 ment the effect of a strongly preconceived idea 

 that the ridges and the patterns which they 

 form are, as the author attempts later to 

 prove, purely tactile in function, and that he 

 assumes that they must, therefore, reach their 

 highest development in man. As a matter of 

 fact, in the case of the hand of man, where 

 certainly the tactile function is most highly 

 developed, patterns are so seldom found, ex- 

 cept upon the apical pads, as to argue con- 

 clusively that the patterns which appear in 

 the lower monkeys and to a certain extent in 

 other mammals are directly associated with 

 and determined by external pressure upon the 

 walking pads or elevated areas, upon the sur- 

 face of which they are developed. 



Part IL furnishes descriptions, with illus- 

 trations from photographs and drawings, of 

 sections through many varieties of volar and 

 plantar skin. If these illustrations were ac- 

 companied by interpretations pointing out 

 clearly the various features shown, they would 



