ORIGIN AND MORPHOLOGY OF GHLOEOPHYLL CORPUSCLES. 251 



words, whether such bodies are to be found in the cells of 

 fungi ; and in connection with this it may be noted that plas- 

 tids have been observed in colourless Phanerogamic plants. 



Until these points are decided we shall be unable to draw a 

 complete comparison between the plastid and the cell nucleus. 

 We have, however, already at hand sufficient knowledge of the 

 subject to allow of some very interesting comparisons being 

 drawn between these two categories. At the conclusion of his 

 paper, Professor Schmitz offers some remarks of the greatest 

 interest on this subject, vphich bring out clearly in how many- 

 points the cell nucleus resembles the chromatophore. Both 

 are formed, at all events in the very large majority of cases, if 

 not exclusively, by division of pre-existing similar bodies; 

 both consist of a ground-substance with a finely reticulate 

 structure, which resembles the protoplasm of the cell ; this in 

 each case encloses bodies (one or more) with a definite outline, 

 consisting of a substance giving similar reactions in either 

 case ; these included bodies behave generally, if not exactly, in 

 a similar manner during the division of the whole ; in both 

 cases coalescence may occur. On the other hand, there are 

 })oints in which the chromatophores and nuclei differ ; thus the 

 peculiar phenomena accompanying division, which are so cha- 

 racteristic in nuclei, are not found in chromatophores. On the 

 above and other grounds, Professor Schmitz suggests that the 

 nuclei and chromatophores may be placed side by side as two 

 series, which have been derived from a common starting point, 

 and have undergone individual modification to subserve dif- 

 ferent physiological purposes. This being the conclusion 

 drawn from the study of the lower green-coloured organisms, 

 the extension of it may be allowed also to the higher plants, 

 the chief difference being that here the chromatophore has 

 undergone further specialisation, as shown in the plastids of 

 the different categories above described. 



It remains to consider the relation of these included bodies 

 to the protoplasm which surrounds them. A new and start- 

 ling view is hinted at by Schimper in a footnote to his paper 

 ('Bot. Zeitg./ 1883, p. 112). He suggests that if it be defini- 



