420 M. H. V. Mohl on the Structure of Chlorophyll 



cavity of the cell, the globules swell into vesicles, their green 

 colour becoming much lighter and the granules lying inside be- 

 coming more distinct. When there are many globules in a cell, 

 and hence the vesicles which they form come to press upon each 

 other, in most cases (at least before the application of iodine) all 

 distinct appearance of detail is lost, and the green contents of 

 the cell seem to have become fused together into an amorphous 

 mass ; a condition undoubtedly often seen in microscopic inves- 

 tigations, but which has mostly been regarded as a mechanical 

 disturbance of the chlorophyll resulting from pressure with the 

 knife, or as a proof of the existence of amorphous chlorophyll. 

 But when the globules lie at greater distances apart in the cell^ 

 or emerge singly into the water, one is enabled to trace more 

 accurately the alterations they undergo from the action of water. 

 These are essentially of the same kind as those above described 

 of the chlorophyll of Zygnema and Anthoceros. In each grain 

 one or more vacuoles are formed, expanding the green substance^ 

 and afterwards breaking through it in the form of colourless 

 vesicles. The green substance sometimes retains its cohesion, 

 and remains hanging as a cup-like cover upon one side of the 

 vesicle, sometimes becomes partially disintegrated, so that sepa- 

 rate pieces of it, distinguishable by their colour or their gra- 

 nules, remain attached, isolated, upon the outer surface of the 

 vesicle ; whereby it is clearly perceived that the mucilaginous 

 substance in which the vacuole lies, bears the green substance 

 on its surface, and does not form a membrane surrounding the 

 green matter. The substance of these chlorophyll-globules is very 

 soft, so that not unfrequently, when the covering- glass is placed 

 upon the object, some of the globules which have escaped into 

 the water adhere to the glass and become pushed up together 

 into a shapeless mass, which then usually assumes a frothy con- 

 dition through the formation of many small vacuoles. That the 

 outermost layer of these chlorophyll-globules possesses a firmer 

 consistence is in the highest degree probable, since otherwise a 

 similar adherence of the globules to foreign substances would be 

 more common, and the mutual pressure would unite the glo- 

 bules into a common mass ; but no trace can be discovered of a 

 true membrane distinct from the internal substance. In my 

 former treatise, I stated it to be probable that the fine granules 

 lying in the chlorophyll, in which, from their minute size, I 

 could not discover whether or not they were coloured blue by 

 iodine (as is the case with the larger granules of the second 

 form), were in like manner starch-grains ; this w^as an error, as 

 the use of better microscopes has now convinced me; these 

 revealing that the granules are coloured brown by iodine, in 

 which they agree with the granules occurring in the protoplasm. 



