DK. M. J. SCHLEIDEN ON PHYTOGENESIS. 283 



lation to the origin of the cell itself. I consequently directed 

 my attention especially to this point, and was so fortunate as to 

 see my endeavoiirs crowned Avith success. 



Before, however, proceeding to the communication of these 

 observations, it is necessary that I should describe somewhat 

 more at length the nucleus of the cell. As I have to treat of an 

 entirely peculiar, and, as it appears to me, of an universal 

 elementary organ of vegetables, I do not deem it necessary to 

 excuse myself for applying to this body a definite name, and 

 shall term it Cytoblast {kvto<; /^Xao-ro?) with reference to its 

 function, which will be subsequently described. 



This formation varies in its outline from oval to circular, 

 according as its solid form seems to pass from that of the lens 

 into the perfect sphere. The oval and flat ones I have found 

 most frequently in monocotyledonous plants, in the albumen, 

 and in the pollen ; the globular chiefly in the Dicotyledons, and 

 in the leaf, stem, articulated hairs, and similar formations j how- 

 ever, no exclusive rule can be asserted in this respect. 



The colour of the cytoblast is in general yellowish, yet some- 

 times passing almost into a silver white. I observed it to be most 

 transparent in the albumen of some water plants, in the unripe 

 pollen, in some Orchidece, and also in the rudiments of the leaf 

 in Crassula portulacea. It is scarcely to be distinguished, on 

 account of its excessive transparency, in the sporidia of some 

 Helvelloids. It is coloured by iodine, according to its various 

 modifications, from a pale yellow to the deepest brown. 



Its size varies considerably. It is in general largest in Mono- 

 cotyledons, and in the albumen ; smallest in Dicotyledons, in 

 the leaf, stem, and their metamorphosed parts. The largest that 

 I have seen was 0*0022 Prussian inch* in diameter (in Fritillaria 

 pyrenaica) ; the smallest in the embryonal extremity of the pol- 

 linic cellule of Linum pallescens, from 0*00009 to O'OOOl Prus- 

 sian inch. In the albumen of Abies excelsa I found it, on the 

 average of several admeasurements of individuals of appa- 

 rently equal size, from 0-00034 — 0-00059 — 0*00079. In the 

 young leaves of Crassula portulacea = 0-00Q^, and in the albu- 

 men o{ Pimelea drupacea = 0-00095 —0-001055. However, httle 

 importance can be attached on the whole to these measurements, 

 as they increase and diminish ; and it cannot be determined in 

 what period of its life the cytoblast is examined. Its internal 



• The Prussian iiicli is to tlie English ua 103 to 1.— En. 



