AN APPRECIATION xi 



have mastered all the methods of crystallographic investigation, 

 especially the optical methods which are all-important. He was 

 able to extend considerably the investigations of Nageli and others 

 upon the form and nature of " crystalloids," and particularly to 

 stud)- the change of form which they undergo in swelling. I think 

 that his remains the standard work on these substances. The 

 crystallographic bearing of the work was published by him in 

 a separate paper. I think he was the first to suggest and to give 

 some ground for believing that some of the " crystalloids " may be 

 isomorphous, e. g. the artificially prepared Mg-, Ba-, and Ca- com- 

 pounds, which appear to have a similar composition and nearly 

 the same form.' 



Schimper's botanical contributions include work of first-class 

 importance in three branches of the subject — histology, oecology, 

 and geographical distribution of plants, as well as some suggestive 

 papers on a fourth branch — physiology. 



Unsurpassed by any histological work of our time was that 

 of Schimper on chromatophores. The first of a series of papers 

 was published in 1880 on 'Starch-producing granules,' in which 

 it was shown that starch arises, not in the general cytoplasm, but 

 in two kinds of homologous protoplasmic bodies, chloroplasts and 

 leucoplasts. Three later papers, issued in 1882, 1883, 1885, upon 

 chromatophores proved the existence of a third form of proto- 

 plasm, chromatophore-protoplasm, as distinct from cytoplasm and 

 nucleus as these are from one another. As Schimper's views 

 are still held by the majority of botanists, it may be said that 

 he revolutionized our ideas as to the constitution of vegetable- 

 protoplasm and as to the unit of plant-life. 



In the meanwhile Schimper had also fundamentally modified 

 botanists' views as to the nature and growth of starch-grains, by 

 his publication in 1881 of a paper upon the growth of these 

 bodies. The nature of the change may be gleaned by the 

 following quotation from an article written by Schimper in the 

 American Naturalist (1881) : — ' Nageli and, after him, most bio- 

 logists hold that starch-grains agree with protoplasm as to their 

 molecular structure, and are to be considered as living bodies.' 

 This paper, in demonstrating the growth of starch-grains by 

 apposition, dealt Nageli's theory of the growth of cell-walls and 



