Botany. 473 



modification of chlorophyll-granules. In 1872 Kraus added some 

 observations regarding ordinary spindle-shaped forms, and stated 

 that they appeared to come from the breaking down of the 

 protein color-granules, but this view was opposed by the fact that 

 these bodies occur even in some very young parts. Millardet 

 (1876) by an examination of the coloring matters in the Iruit of 

 the tomato, made out some of the relations existing in many cases 

 between chlorophyll-grains and color-granules. It was shown by 

 him that these could change into one another under certain cir- 

 cumstances, and that they possibly had a common origin. This 

 link was partly supplied in J 880, by Schimper, who announced 

 the discovery in certain cells containing starch, of colorless gran- 

 ules, which had the function of collecting from the nutrient cell- 

 sap the materials for the construction of starch grains. These 

 bodies were termed by him starch-formers. After pointing out 

 their occurrence and indicating the precautions necessary for 

 their detection, he hints that they have close relations to the other 

 living proteid granules in the vegetable cell. Soon after this, 

 several investigators took the subject up, notably Meyer, while 

 Schimper himself made a most important advance. This step 

 consisted in coordinating all the granular living proteid granules, 

 holding that color-granules and chlorophyll-granules are derived 

 from the colorless granules found in the cells at the growing 

 points of plants. For these bodies the common appellation of 

 plastids or plasts was proposed, with the distinctive prefixes, 

 leuco-, chloro-, and chromo-. About this time, or a little before, 

 Van Tieghem suggested the term leucites for the same thing. 

 Although Schimper's terms have been generally adopted, Courchet 

 prefers Van Tieghem's. Schimper teaches that these plasts arise 

 from pre-existing plasts, and that they assume the special form 

 of leucoplasts, chloroplasts, or chromoplasts, according to the 

 office of the part and the conditions under which they are devel- 

 oped. The morphological interest attaching to the organs of a 

 plant is greatly heightened, when it is seen that in the cells 

 themselves which constitute them, there are adaptations not 

 merely in form but in the granular differentiations of the living 

 matter. Just as a foliar expansion can be turned to account by 

 the plant in many different ways, as a foliage-leaf, as a tendril, as 

 a fly-trap, as a thorn, or as a pitcher, so can these simple proteid 

 granules undergo modifications adapting them to the most diverse 

 kinds of work. From the point of view of evolution the subject 

 is of great importance, clearing up some serious difficulties in the 

 way of explaining the adaptation of colors in flowers and fruits 

 to the visits of insects and of birds. The diversified shapes of 

 foliar and floral organs have been rather easier to understand 

 than the marvellous range ol useful colors in these parts of the 

 plant, but it is now apparent that all of them may arise from the 

 very simplest starting point common to all. 



In all important features, Courchet confirms Schimper's views, 

 and. they may be considered as in the main firmly established. 



