ATLAS 



OF THE 



FERTILIZATION and KARYOKINESIS 

 of the OVUM 



By EDMUND B. WILSON, Ph.D., 



Professor of Invertebrate Zoology in Columbia College 



WITH THE CO-OPERATION OF 



EDWARD LEAMING, M.D., F.R.P.S., 



Instructor in Photography at the College of Physicians and Surgeons, Columbia College 



WITH TEN PHOTOGRAPHIC PLATES AND NUMEROUS DIAGRAMS 



Extra 8vo. Cloth, pp. vii + 32. $4.00, net. 



This work comprises forty figures, photographed from nature by Dr. Learning from the 

 preparations of Professor Wilson at an enlargement of one thousand diameters, and 

 mechanically reproduced by the gelatine process, without retouching, by Edward Bierstadt 

 of New York. The plates are accompanied by an explanatory text, giving a general intro- 

 duction to the subject for the use of students and general readers, a detailed description 

 of the photographs, and over sixty text-figures from camera-drawings. 



It is the object of this atlas to place before students and teachers of biology a practically 



continuous series of figures photographed directly from nature, to illustrate the principal 



phenomena in the fertilization and early development of the animal egg. The new science 



of cytology has in the course of the past two decades brought forward discoveries relating 



to the fertilization of the egg and the closely related subject of cell-division (karyokinesis) 



that have called forth on the part of Weismann and others some of the most important 



and suggestive discussions of the post-Darwinian biology. These discoveries must in 



some measure be dealt with by every modern text-book of morphology or physiology, yet 



they belong to a region of observation inaccessible to the general reader or student, since 



it can only be approached by means of a refined histological technique applied to special 



objects not ordinarily available for practical study or demonstration. A knowledge of the 



subject must therefore, in most cases, be acquired from text-books in which drawings are 



made to take the place of the real object. But no drawing, however excellent, can convey 



an accurate mental picture of the real object. It is extremely difficult for even the most 



skilful draughtsman to represent in a drawing the exact appearance of protoplasm and the 



delicate and complicated apparatus of the cell. It is impossible adequately to reproduce 



the drawing in a black-and-white text-book figure. Every such figure must necessarily be in 



some measure schematic and embodies a considerable subjective element of interpretation. 



The photograph, whatever be its shortcomings (and no photograph can do full justice 



nature), at least gives an absolutely faithful representation of what appears under the 



roscope ; it contains no subjective element save that involved in the focussing of the 



" +r ument, and hence conveys a true mental picture. It is hoped, therefore, that the pres- 



*ork may serve a useful purpose, especially by enabling teachers of biology to place 



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