304 The Physiology of Plants BOOK in 



was the classic research of Schimper into the mode of for- 

 mation of starch grains not only in the chloroplastids, but 

 also throughout the plant, This is scarcely the place to 

 discuss the whole of this investigation, but it raised a very 

 important consideration in view of the theory formulated 

 by Sachs, which has already been quoted. Schimper found 

 that starch grains appear in the interior of plastids situated 

 in the parts of plants not normally exposed to light, and 

 that they are the consequence of a supply of sugar reaching 

 such corpuscles. He also showed that when these colourless 

 corpuscles or plastids are exposed to light, they develop 

 chlorophyll like the plastids of the leaves. A fair deduc- 

 tion follows, viz. that sugar precedes starch in the formative 

 processes, and that in all probability these processes 

 culminate in its construction, starch formation being a 

 subsequent and secondary matter, alike in colourless and 

 coloured plastids. Schimper himself writes on the general 

 question : * 



' It is clear that the starch which appears as the first 

 evident product of assimilation in the true chlorophyll 

 corpuscles does not originate directly from carbon dioxide 

 and water, but that more or less numerous intermediate 

 products still unknown, or at any rate known with less 

 certainty, are interposed.' 



These views at first seemed to be opposed to the position 

 of Sachs, and were interpreted in that sense by contem- 

 porary writers. They did not appear so to Sachs himself, 

 who, quoting from Schimper in 1882, went on to complain 

 of being misrepresented by the writers alluded to, and 

 pointed out the views he propounded were not antagonistic 

 to those of Schimper, whose work he cordially accepted. 

 He reminded his readers 2 that he stated in his Experi- 

 mentalphysiologie in 1865 : 



1 Quoted by Sachs in Vorlesungen, Eng. ed., p. 317. 



2 Vorlesungen, Eng. ed., p. 317. 



