THE VEGETABLE CELL. 43 



it appear at a later period in tlie perfect chlorophyll globules, and 

 increase in size with the age of the plant. Thus it seems to nae 

 that starch does not stand in any causal and necessary connexion 

 with chlorophyll, but that the proteine substance combined with 

 chlorophyll sometimes assumes the definite form of globules, 

 bands, &c., and sometimes, when starch granules are present, be- 

 comes deposited on these as upon a nucleus. 



Observ, The relation of chlorophyll to starch i& viewed in an essen- 

 tially different way by Mulder, who rests upon my description of the 

 former. He assumes that the chlorophyll granules are always produced 

 from starch granules, since the latter become partly or wholly converted 

 into the wax connected with the green colouring matter, and in so doing 

 either assume the form of globules or become blended together, and pro- 

 duce amorphous chlorophyll. This ti^ansformation of starch into wax 

 must be accompanied by an abundant evolution of oxygen gas ; and 

 Mulder therefore beheves that plants do aot exhale this gas because they 

 are green, but while they are becoming green. I cannot accept this 

 theory on account of anatomical reasons, for in many young organs we 

 find chloi-ophyll but not starch, which should precede it, and in the Oo?i~ 

 fervcB particularly, in which the chlorophyll occurs in the form of bands 

 and plates, as in Zygnema^ &c., these structures never consist of a sub- 

 stance having any resemblance to starch, but, on the contrary, the starch 

 granules occuixing in this chlorophyll increases in size with the age of the 

 plant. 



Ohserv. 2. I have described the chlorophyll granules as a softish, homo- 

 geneous substance, and not as utricular structures, such as they were 

 formerly stated to be by Sprengel, Meyen, Agardh, Turpin, and others, 

 for I never could succeed in discovering upon them an enveloping mem- 

 brane distinct from the contents. Their utricular nature has, however, 

 been defended in recent times by Kageli. ("Zeitschr. f. vjiss. Botan" 

 iii. 110); according to his statements, a wliitish membrane and green 

 contents may be clearly distinguished in the large chlorophyll granules of 

 the Algse, Charge, and Mosses. Also Goppert and Cohn {"Mot Zeit'^ 

 1849, ^^6) say that in Nitella they saw the chlorophyll granules ex- 

 pand by absorption of water into vesicles composed of a thhi translucent 

 membrane, which finally burst. I am not in a position at the present 

 moment to test these statements respecting the chlorophyll granules of 

 Nitella; but I have formerly jBrequently examined them and detected the 

 occuiTence of starch granules in the chlorophyll, but could never find a 

 membrane upon the latter. ISTageli believes, moreover, not only that he 

 has seen a membrane in many cases, but that he has found proof of a 

 complete analogy of these vesicles, with cells, in the phenomena of their 

 vegetation. In this he is not warranted by a single fact ; for that the 

 chlorophyll granules may grow, and during growth alter in form, is no 

 proof at all of the cellular nature, any more than is the circumstance that 

 their number may be multiplied by division as in Nitdla. Division 

 might occur in globules devoid of a membrane j but that it depends on 

 the formation of secondary vesicles inside the chlorophyll vesicles, is an 

 hypothesis devoid of all foundation. 



Obmr'V. 3. We know very little as yet of the anatomical conditions of 



