August 13, 1909] 



SCIENCE 



215 



brief accounts of later work. However, for 

 the greater part of these two volumes, the 

 article Bewegung der Hydrosphare in Vol. 

 VI., 1, 6, of the " Encyklopiidie der mathe- 

 matischen Wissenschaften," by Darwin and 

 Hough, will be found to supply these needs. 

 This articl^ is to be reproduced, it is to be 

 hoped in English, in Volume IV. of the " Sci- 

 entific Papers." 



I may mention one point in conclusion in 

 connection with Sir George Darwin's presen- 

 tation of his work which earns the gratitude 

 of those who are unable from want of time or 

 training to read his papers in detail as well as 

 of those who do such reading but wish to get 

 a general view of his processes and results as 

 a first step. In the summaries to the longer 

 memoirs he gives not only the general con- 

 clusions at which he has arrived, but also a 

 brief account, without symbols, of the hypoth- 

 eses on which the argnments are based, the 

 methods employed and the general course of 

 the mathematical procedure. These summaries 

 have made the task of following his work very 

 much less difficult and have doubtless con- 

 tributed in some measure to the early accept- 

 ance of the theories which he has set forth. 



The printing done by the Cambridge Uni- 

 versity Press is too well known to need com- 

 ment here. The size of the volume adopted is 

 the modern compromise between convenience 

 for the printing of long formulae and suitabil- 

 ity of size for easy handling and reading, 

 namely, the royal octavo between one and two 



inches thick. ,-, ttt -n 



Ernest W. Brown 



The Prohlem of Age, Growth and Death: A 

 Study of Cytomorphosis based on Lectures 

 at the Lowell Institute, March, 1907. By 

 Charles Sedgwick Minot. New York and 

 London, G. P. Putnam's Sons. 1908. Pp. 

 280; good index. 



Many biologists, and with them a wide cir- 

 cle of people who are intelligently interested 

 in fundamental problems of life, have fol- 

 lowed Professor Minot's researches in this 

 field with keen interest for thirty years past, 

 and will be glad to have the many scattered 

 papers collected in book form and brought 



down to date. The purpose of the book is 

 stated in the elaborate " introductory letter," 

 which is addressed to Senator Mosso, to whom 

 the work is inscribed. It is a study of " in- 

 crease in the amount of protoplasm " as com- 

 pared with the bulk of nucleus in the cells of 

 the growing animal. 



The first lecture deals with the process of 

 growing old as seen in the body as a whole; 

 and while the familiar data are exceptionally 

 well presented, it calls for no special review. 

 The second lecture, " Cytomorphosis — the Cel- 

 lular Changes of Age," carries a somewhat 

 parallel line of thought through the microscop- 

 ical changes in the cells and tissues' from the 

 germinal to the senescent condition. Here we 

 learn, in connection with appropriate figures 

 in the text, about the " cytomorphic cycles " 

 of different cells, connective tissne, nerve, 

 muscle, gland and blood; and of the death and 

 old age of cells in atrophy or degenerations of 

 various kinds. As cells differentiate from the 

 germinal to the adult form they become fitted 

 to perform specialized functions, but lose the 

 germinal power of growth and regeneration. 

 Thus death is continually present in life, and 

 may be even more active in the embryo, as, in 

 the rapid whirl of cell-life, whole organs form 

 and vanish, than during any other period of 

 life. In fact one of the main theses is that: 

 "The period of most rapid decline is youth; 

 the period of slowest decline is old age." 



The third lecture—" The Eate of Growth," 

 gives the results of the author's extensive 

 studies on the growth of guinea-pigs, rabbits 

 and fowls and correlates them with those of 

 Quetelet, Donaldson, Muhlmann and Thoma 

 for man. The facts are presented with great 

 precision in text, table, series of figures of 

 embryos and by most striking charts and 

 curves, growth being expressed, in the main, 

 in percentage increments. The chief result is 

 that power to grow is greatest in the germ and 

 decreases rapidly with age. For example, 

 using Richard Hertwig's calculation, the fer- 

 tilized human ovum is 0.004 of a cubic milli- 

 meter; the child at birth from 3 to 4,000,000 

 cubic millimeters, which shows an increase of 

 one billion times the original mass during 

 gestation. From birth on to twenty years of 



