1870.] Notices of Scientific Worhs. 373 



say in conclusion, that we have heen much charmed hy the perusal 

 of the work. It is in many places very poetical ; its author shows 

 himself to be a careful and earnest observer, and the novel aspects in 

 which old phenomena are presented to the reader are deeply in- 

 teresting and often startling. The beautiful chromo-lithographs 

 are amongst the best we have seen, and they convey vivid impres- 

 sions of the heavenly bodies which they are intended to represent. 



COMPAEATIYE LONGEVITY.* 



Mr. Lankester has published an Oxford prize essay on Longevity, 

 and his little book merits the attention of a wider circle of readers 

 than it would be likely to find within the precincts of the University. 

 The title was, of course, not of the author's choosing, and as ori- 

 ginally given out was as follows : — ' The Comparative Longevity of 

 different Species of Lower Animals, and the Longevity of Man in 

 different States of Civilization.' As the author very properly says 

 in his preface, " The subject does not admit of very satisfactory 

 treatment from a scientific point of view, and is accordingly one 

 which probably few persons would have selected to write upon, 

 unless under special circumstances," "but at the same time," he 

 remarks, " longevity is a subject of great popularity, and hence the 

 facts and arguments herein set forth may, it is hoped, interest the 

 public." 



Although we should not feel justified in complimenting the 

 author upon his treatment of the question from any other than a 

 scientific point of view, and are unable to accredit him with success 

 in having imparted greater popularity to this subject, we have no 

 doubt that the essay will materially add to his rapidly increasing 

 reputation as an accurate observer and promising naturalist, for every 

 page bears evidence of careful thought and extensive reading. 



In conformity with the apparent wishes of the examiners or 

 judges, he has divided his subject into two sections, the first of 

 which treats of longevity in organisms generally, and the second 

 of longevity in man. 



His definition of longevity would be apt to puzzle non-scientific 

 readers, for it is " the length of time during which life is exhibited 

 in an individual ;" but the meaning intended to be expressed, as 

 subsequently explained, is that it is the " potential duration of life " 

 in an " individual," as distinguished from a group or succession of 

 individuals, as in the case of asexually-produced polyps, for ex- 



* ' On Comparative Longevity in Man and the Lower Animals.' By E. Kay 

 Lankester, B.A., Oxon. Macmillan & Co. 



