starch-grains to be found in chloroplastids are the first visible pro- 

 duct of their assimilatory activity. This period of Sachs' life Ava.s 

 that in which he first made his mark as a writer of books. In 1865 

 appeared his ' Handbuch der Experimental-Physiologie der Pflanzen ' 

 (as vol. 4 of the uncompleted ' Handbuch der Physiologischen Botanik,' 

 edited by Hofmeister) ; and although his well-known ' Lehrbuch der 

 Botanik '* was not actually published until 18G8, the work fairly 

 belongs to the period under consideration. In neither of these books 

 do w r e find much indication of that literary ability which marks 

 his later works, no doubt because their structure rendered any 

 attempt at literary form impossible. They are both of them mines of 

 information, especially as regards the older botanical literature. But 

 they are much more than this. Though they may both be included 

 under the designation "text-book," unlike most text-books they con- 

 tain a large mass of original work on the part of the author. Thus, 

 they are not only learned, but also stimulating. It is not too much 

 to say that they have contributed very largely to the unprecedented 

 expansion of morphological and physiological research which has 

 taken place since their publication, a statement which is especially 

 true with regard to this country. They are generally admitted to be 

 the best works of the kind which had appeared up to that time, and 

 although they have now become somewhat antiquated, it is doubtful 

 if they have been excelled by any such works which have appeared 

 since. One feature in them deserves special notice, and that is the 

 manifestation, in the illustrations of the ' Lehrbuch ' in particular, of 

 the remarkable artistic faculty wdrick Sachs possessed. 

 * The preparation of the earlier editions of the ' Lehrbuch ' is no 

 doubt accountable for the relatively small number of original 

 memoirs which Sachs published during the years 1865-72, a period 

 which included his brief sojourn at Freiburg and his settlement at 

 Wiirzburg. But he had not been long in Wiirzburg before he 

 resumed his researches, the more important of which were published, 

 together with contributions by his colleagues and pupils, in the 

 well-known ' Arbeiten des Botanischen Instituts in Wiirzburg,' the 

 first number of which appeared in 1871. His papers in the first 

 volume of the ' Arbeiten ' (1871-74) all have reference to the 

 phenomena of growth, and include his remarkable investigations 

 into the periodicity of growth in length, which clearly established 

 the retarding influence of the highly refrangible rays of the spectrum. 

 The contents of the second volume (1878-82) are of very great 

 interest. We find here the last of his researches on growth, intro- 

 ducing the " clinostat," an important addition to the apparatus of 



* Ad English translation of the third Grerman edition was published by the 

 Oxford University Press in 1875 ; and another, from the 4th Grerman edition 

 (1870), was publisher in 1882. 



