April 1, 



3.] 



SCIENCE. 



463 



a place on the list, at the age of 18 years. The 

 editor, on the other hand, fixes the age at 40 

 years. Professor Jastrow in Science, volume 

 8, fixes the age in question at 37 years. We 

 have thus three opinions as to the data and, 

 naturally, three results. After examining these 

 three opinions I venture to add a fourth — 

 namely, that the age fixed by Lancaster is too 

 low ; that the editor's is much too high and 

 that Professor Jastrow' s is somewhat too high. 

 Jastrow's conclusion is : "Men of thought live 

 69.5 years, or 3.5 years longer than ordinary 

 men, while the lives of men of feeling [poets, 

 musicians, artists, etc.] are three years, those 

 of men of action five years shorter than those 

 of average men. ' ' These statements show ' that 

 the kind of psychical and physical activity in- 

 fluences the life period.' Quantitative results 

 in this matter are only to be reached after a 

 critical study of the data. Neither Lancaster 

 nor the editor have made such a study. The 

 assumption of Professor Jastrow is so based, 

 but the details of his processes are not given. 

 I am inclined to think that for astronomers his 

 figures are too low. 



Edward S. Holden. 

 March 20, 1898. 



To THE Editor of Science: In the matter 

 of the longevity of scientific men, I should like 

 to direct the attention of your readers to an 

 article which I published in Science of October 

 1, 1886 (reprinted in Nature November 4, 1886). 

 I there considered the erroneous conclusions as 

 to the longevity of astronomers and mathema- 

 ticians, which Professor Holden has recently 

 revived. Inasmuch as I had available in the 

 case of a considerable number of great men the 

 approximate date at which they accomplished 

 work, which would presumably entitle them to 

 a place on this list, I was able to compare more 

 exactly the average longevity of these great 

 men with the average longevity of ordinary 

 men who had reached a similar age. This age 

 I found to be about 37 years, which, with the 

 expectation of life at that age, namely 29 years, 

 would make the age at death 66 years, which 

 was precisely the age at death of the great men 

 selected for this comparison. It is quite pos- 

 sible that men of science live longer than other 



great men; but, if so, it would, of course, be 

 only a very modest increase of years consistent 

 with the known laws of variation. 



Joseph Jasteow. 

 University of Wisconsin, 

 March 20, 1898. 



SCIENTIFIC LITERATURE. 



A NEW edition OF ECKEE'S PROG.* 



There is probably no single animal, man 

 excepted, which is more studied than the frog. 

 It can be had in quantities ; it presents the 

 characters of the vertebrates in a comparatively 

 simple condition, and hence it is used in every 

 zoological course, while the vitality of its tis- 

 sues renders it of extreme value to the physi- 

 ologist. Naturally, such a useful animal has 

 been the subject of considerable literature, and 

 outlines of its structure will be found in almost 

 every laboratory manual. Most of these, how- 

 ever, present only outlines, but in 1864 Alex- 

 ander Ecker, then professor of anatomy in the 

 University of Freiburg, began the publication of 

 what was intended to be an exhaustive account 

 of the anatomy of the common frog of Europe. 

 Ill health, and finally death, prevented his com- 

 pletion of the work, but it was taken up and 

 carried through by Wiedersheim, who suc- 

 ceeded Ecker in the anatomical chair, the final 

 part appearing in 1882. Later (1889) an En- 

 glish edition of the work appeared, but this 

 was more than a translation, for its editor. Dr. 

 George Haslam, left his impress on every 

 chapter, his changes in some instances amount- 

 ing to a complete revision of certain sections. 



Now a new German edition is in process of 

 publication, audit is interesting to note that the 

 new editor, like his predecessors, is connected 

 with the anatomical institute of the University 

 of Freiburg. Professor Gaupp began his studies 

 of the frog in 1892, and since that time most of 

 his publications have related to that animal, its 

 skeleton and its muscles ; especially noteworthy 



*A. Eoker's und R. Wiedersheim's Anatomie des 

 Frosches auf grund Untersuchung durchaus neu 

 beaibeitet von Dr. Ernst Gaupp. Erste Abtheilung, 

 dritte Auflage. Braunschweig, Vieweg und Sohn. 

 1896. Pp. x+229. Zweite Abtheilung, erste Halfte, 

 zweite Auflage. Brunsohweig. 1897. Pp. ii-l~231. 

 22 Marks. 



