Experimental Morphology

Abstract

THE second part of Dr. Davenport's work—the first part appeared two years ago and was noticed in NATURE, October 14, 1897—deals exclusively with the effect of chemical and physical agents upon the growth of animal and plant organisms. In the preface the author draws attention to the importance of the study of the conditions which affect growth. “The possibility of increasing the human race beyond limits that are not far off depends upon a better knowledge of the conditions of growth. The reader has only to consider that the world's supply of 2500 million bushels of wheat, 2000 million bushels of maize, 90 million tons of potatoes, and its untold millions of tons of beef, pork, and fish are reproduced each year by growth.” This importance has recently been emphasised by the remarkable result of Sir William Crookes' researches into the statistics of the world's wheat supply as set forth in his presidential address at the Bristol meeting of the British Association, and the controversy to which that address has given rise. Dr. Davenport selects as his definition of growth “increase in volume,” a definition which is by no means safe from criticism. Although we all think we understand what is meant when growth is spoken of, biologists have been by no means in agreement as to how exactly it should be defined. Thus, as the author points out, while Huxley spoke of growth as “increase in size,” Sachs regards the volume increase as necessarily intimately associated with change of form, while Pfeffer takes the qualifying part of Sachs' definition, and defines growth as change in form only, and this is accepted by Vines, who adds: “accompanied usually by increase in bulk.” To us this definition appears far more satisfactory, even if it is associated with the idea of development, than the more limited definition adopted by Davenport. In the animal organism especially is it difficult to exclude the idea of change of form in association with growth, nor does it seem reasonable to place a mere swelling due to imbibition of water or to distension with gas upon the same footing as a new formation of bioplasm.

Experimental Morphology.

By Charles Benedict Davenport, Instructor in Zoology in Harvard University. Part 2. Pp. xviii + 281 to 508. (New York: Macmillan Company; London: Macmillan and Co., Ltd, 1899.)