162 SCIENCE PROGRESS. 



himself: " I am beginning to take private pupils again," he 

 writes, " but there is little pleasure in it. When a professor 

 reaches the age of sixty, he ought eo ipso to be pensioned 

 off with his full salary ; it might be possible to arrange a 

 university that would serve as an almshouse but I would 

 not go into it." 



He urged his pupils to make comprehensive studies 

 even as he was constantly striving after wide generalisa- 

 tions. He was a master in the art. We have only to 

 think of his Experimental Physiology, his Text-book in 

 four editions, his History of Botany and his Lectures on 

 the Physiology of Plants. Although he wrote with ease, 

 he bestowed great care upon composition, and usually 

 made several rough sketches before the work was done to 

 his satisfaction. In later years he generally dictated, and 

 the Lectures were written in this way. The great debt 

 owed by modern botany to his Text-book can scarcely be 

 appreciated even yet by the younger generation of 

 botanists. 



No entirely satisfactory text-book had appeared since 

 Schleiden's Outlines, a book that contained much that was 

 critically suggestive, but, on the other hand, was one-sided 

 and tinged by the author's personal prejudices ; nor had 

 the later editions of it been brought up to date with the 

 advance of science. Sachs' book was the first to make 

 Nageli's and Hofmeister's researches known to the world. 

 It was written in an unusually clear, literary style, and 

 contained all that was best according to " the present state 

 of science " as the title-page says, especially the author's 

 important physiological researches. The letter-press was 

 interspersed with numerous illustrations, chiefly Sachs' own 

 work and not seldom the results of laborious, tedious ex- 

 periments. These illustrations have been frequently re- 

 produced and, contrary to Sachs' express wish, have become 

 common property. Too often it has been considered quite 

 unnecessary to obtain his consent to the use of the figures, 

 and the appearance of a newer text-book decked out with 

 his own illustrations elicited from him the somewhat bitter 

 though just remark, that a student, using this book, would 



