BoT— Vol. I.] LAWSON—COBy^.A SCANDENS. 1 73 



the writer has made very few observations. They will 

 therefore not be discussed farther. The linin now appears 

 in the form of a lumpy or granular thread ; it stains blue 

 and is invariably connected with the chromosomes. 



The cytoplasm now appears in the form of a clear retic- 

 ulum, as shown in fig. i. The meshes of this network, 

 which can be traced from the nuclear wall to the cell-wall, 

 appear to be smaller and radially elongated in the imme- 

 diate neighborhood of the nucleus; but as one follows 

 them outwards they increase in size and are comparatively 

 large towards the cell-wall. 



Scattered irregularly through the cytoplasm are numerous 

 small spherical bodies. These bodies have the appearance 

 of oil-globules in the living cell, but after the cell has been 

 killed in Flemming's fixing fluid they appear quite black. 

 What the chemical nature or function of these bodies is, 

 the writer is unable to state. 



The cytoplasm does not maintain its clear, uniform 

 appearance for a very long period, but soon undergoes a 

 remarkable differentiation. This differentiation is shown 

 in figs. 2-5. It is brought about by the gradual accumula- 

 tion of a granular substance which forms a complete zone 

 about the nucleus. The minute structure of this substance 

 is difficult to make out, but it appears to consist of granules 

 which vary in size. While some are very minute, others 

 are comparatively large. They appear to be arranged in 

 such a manner as to give the impression of a foam-structure. 



This granular . zone is so constant in Cobcea and in 

 several other genera observed by the writer, that for con- 

 venience it will be called perikaryoplasm. While it is 

 accumulating, the black bodies, which were previously 

 scattered irregularly through the cytoplasm, take up a 

 definite position. They arrange themselves along the outer 

 margin of the perikaryoplasm, and in section present the 

 appearance of a complete ring, as shown in fig. 5. 



It is at this stage that the contrast between the outer 

 cytoplasmic reticulum and the perikaryoplasm is greatest. 

 The threads of the outer reticulum now appear to have no 



