July 25, 1902.] 



SCIENCE. 



145 



(axial or direction relations) is determined 

 rather in the sense of a mosaic-work by self- 

 differentiation; in other cases, on the con- 

 trary, it may be due to differentiation depend- 

 ent upon the regulatory influences of the whole 

 upon its parts. In many cases both these prin- 

 ciples of development are commingled, fre- 

 quently in a marvellous manner, in the forma- 

 tion of some complicated part, so that we must 

 endeavor to determine by a thorough analysis 

 in what respect self-differentiation and in 

 what dependent differentiation predominates." 



And again, "It is a question * * * whether 

 the possibility of 'analyzing animal ontogeny 

 into a series of induction phenomena ' 

 (Herbst) is conceivable, or whether still other 

 components must be recognized. In this con- 

 nection there is especially noteworthy the 

 newer standpoint of Driesch, who, from the 

 problem of the localization of the develop- 

 mental processes, has been led to the opinion 

 that other special vital components, which he 

 figuratively terms forces acting fromi a dis- 

 tance, must be recognized. We are not yet 

 convinced that the former of the possibilities 

 mentioned above is at present to be regarded 

 as completely excluded, and in this respect we 

 agree with the conclusions of von Hanstein." 



The fourth and fifth chapters, which com- 

 plete the volume, treat of the ovum and oo- 

 genesis and of the spermatozoon and sperma- 

 togenesis. Here again there can be only 

 praise for clearness in the arrangement of the 

 topics and in their presentation, and it may 

 be added that, for the sake of thoroughness, 

 the germ cells of the vertebrates as well as of 

 the invertebrates are brought within the scope 

 of the discussion. 



One is tempted to predict for the 'Lehr- 

 buch,' when completed, an influence upon 

 embryological research as great as that ex- 

 erted by Balfour's classic 'Comparative Em- 

 bryology.' Nowhere will there be found a 

 work presenting more perfectly the facts and 

 problems of embryology, and the gratitude of 

 all zoologists is due to the authors for placing 

 in their hands a book so reliable and authori- 

 tative. The concluding volume, which is to 

 treat of maturation and fertilization, the gen- 

 eral phenomena of segmentation and the for- 



mation of the germ layers, is promised at an 

 early date. 



J. P. McM. 



Among the Water-fowl. Observation^ Ad- 

 venture, Photography. A Popular Narra- 

 tive Account of the Water-fowl as found 

 in the Northern and Middle States, and 

 Lower Canada, East of the Rocky Moun- 

 tains. By Herbert K. Job. New York, 

 Doubleday, Page & Co. 1902. Square 

 12mo. Pp. xxi+224, with many illustra- 

 tions from photographs by the author. 

 Hunting with the camera has the double 

 advantage of not decreasing the numbers of 

 birds, while placing the results of the chase 

 at the disposal of the public, instead of reserv- 

 ing it for a chosen few. In the present vol- 

 ume Mr. Job presents the results of many 

 days' enthusiastic labor on the ponds and in the 

 marshes of Dakota, on the Magdalen Islands 

 and the historic Bird Eoeks, and among the 

 islands off the New England coast. From 

 these we get a very clear idea of the breeding 

 habits of many of our water-fowl; we learn 

 how the auk and murre build no nest at all, 

 are introduced to the slatternly homekeeping 

 of the grebes and are shown the well-built 

 and warmly lined nests of the ducks. Most 

 of the water birds that breed within the limits 

 of the United States have posed in front of 

 Mr. Job's camera, or if not the birds, their 

 nests have been photograiihed. And of ducks 

 alone the aiithor tells us he has found the 

 nests of nineteen species. Perhaps the most 

 interesting chapters are those relating to the 

 grebes, since from their manner of breeding 

 the nests are not readily accessible; and these 

 nests are so low and so carelessly built that 

 the loss of eggs must be very great. Mr. Job 

 aptly terms the grebes 'the submerged tenth,' 

 and in reading his accouiit one is led to wonder 

 if that great diver of old, Hesperornis, bred 

 after the fashion of the grebes, since he must 

 have been even more aquatic in habit. 



It is not pleasant to recall that these same 

 grebes are being slaughtered by thousands on 

 their breeding grounds in California, and it 

 is even more painful to read of the shooting 

 of breeding birds on the Great Bird Rock. 



