ORIGIN AND MORPHOLOGY OF CHLOROPHYLL CORPUSCLES. 243 



however, as the result of this part of his study that he arrived 

 at conclusions which diverge from those of Schimper. These 

 may be shortly stated as follows. The Trophoplasts (plastids) 

 have always a skeleton which is resistent to ordinary dissolving 

 media; they also contain substances easily extracted by various 

 dissolving media, which are often embedded in the skeleton as 

 larger or smaller granules: of the latter the best known are chlo- 

 rophyll and xanthophyll. When the Trophoplast (plastid) 

 develops as a typical Autoplast (Chloroplastid), the skeleton is 

 bulky and includes large quantities of chlorophyll ; when it 

 develops as a typical Chromoplast, only a meagre skeleton is 

 formed, and this is again partially absorbed long before the 

 death of the cell ; while the xanthophyll, which is chemically 

 allied to chlorophyll, and is the yellow substance of Chromo- 

 plasts in flowers and fruits, is present in large quantities. 



The latter substance is insoluble in water, and may be 

 obtained macrochemically as yellow crystals, similar to those 

 which are found in flowers and fruits. Not only may all three 

 derivatives of Trophoplasts include starch-grains, but also 

 Autoplasts (Chloroplastids) andAnaplasts (Leukoplastids) may 

 contain crystalloids. 



Thus the point at issue between Schimper and Meyer is 

 this : the former holds that the crystalline form of non-active 

 plastids is that which would be assumed by the substance 

 which forms the proteid basis or skeleton of the plastid, while 

 the colouring matter is carried mechanically with the crystal- 

 lising proteid, or is extruded from it, and remains attached to 

 the surface of the crystal. Meyer, on the other hand, main- 

 tains that the crystalline form is that which would be assumed 

 by the colouring matter, or by a crystalloid, independently of 

 the basis or skeleton, which, in cases where crystallisation 

 occurs, is previously reduced in bulk. 



The controversy on this and allied points is still continued,^ 

 but the details of it are hardly suitable to a paper like the 

 present, and readers must be referred to the original publica- 



1 Meyer, 'Bot. Zeit.,' 1883, Nos. 30—32. Schimper, ' Bot. Zeit.,' 1883, 

 No. 49. 



