404 Vegetable Physiology. 



does not absorb water so readily, and exhibit the " water-bubbles'* 

 above described. The application of water to chlorophyll-granules 

 set free, only causes the line bounding the contained starch granule 

 or granules to become better defined. The chlorophyll-granules 

 containing starch usually acquire larger size than those in which, 

 it is not formed. 



The starch-granules found in chlorophyll are by no means 

 permanent deposits ; they occur during very active vegetation, 

 and vanish again (by solution ?) in subsequent stages of develop- 

 ment. They disappear in this way from the chlorophyll of 

 leaves in autumn ; but the phenomenon is especially well seen in 

 the Ccmfervoid Alga^, where the starch regularly disappears pre- 

 paratory to the cell-division or the conversion of the green cell- 

 contents into spores or reproductive cells. 



The character of these corpuscles of chlorophyll containing 

 starch-granules, has been interpreted in a different way ; they have 

 been regarded as starch-granules which have become encrusted 

 by chlorophyll, the order of development having been assumed to 

 run in the reverse direction from that just described. This has 

 formed the basis for a chemical hypothesis of the origin of chlo- 

 rophyll, which however fails not only on this ground, but also 

 on its chemical basis, since it assumes at the same time that 

 chlorophyll consists simply of the green-coloured fatty matter, 

 leaving out of view the albuminous basis demonstrated by the 

 experiments related in a preceding page. Mulder considered 

 that fatty matter of chlorophyll was formed out of starch bj- a 

 decomposition in which a quantity of oxygen was liberated. The 

 process of conversion was supposed to extend inward from the 

 surface to the interior of the pre-existing starch-granules. The 

 origin of the green colouring substance (existing in very minute 

 quantity), admitted to contain nitrogen, was not satisfactorily 

 explained. 



This hypothesis is in contradiction — first, to the essential 

 nature of the solid basis of the chlorophyll-granules, a mass of 

 protoplasmic or albuminous substance; secondly, to the observed 

 history of development of the chlorophyll-granules which contain 

 starch-granules ; and, thirdly, to the fact, confirmatory of the 

 evidence on the second ground, that chlorophyll-granules originate 

 in cells of young organs wherein no trace of starch can be detected 

 until afterwards. Still more striking are the cases of the green 

 bands of Spirogyra and other Confervoid Algae, which are never 

 preceded by a starchy deposit of the same form. 



Cases do indeed occur where chlorophyll-granules containing 

 starch-granules increase in size, the starch-granules forming a 

 " nucleus " for the chlorophyll ; but that the starch affords the 

 material for the production of the chlorophyll is in opposition to 



