573 
Constituents of the Cell. 
the mother-cell, one pair of centrospheres can be made out. 
Again, in the single isolated spore-cell of Osmunda cinna- 
momea (Fig. 9), these bodies are very distinct. 
Farmer has lately published (’95) a detailed account of his 
studies of pollen-mother-cells of Lilium Martagon , which 
were briefly described in an earlier note (’93). He finds 
spindle-threads converging towards various irregularly placed 
granules in each spindle, and fails to recognize definite centro- 
spheres. His published figures are largely reproduced from 
photographs of the objects, and he has had the goodness 
to send me several prints from the original negatives. It 
must be said that these figures do not arouse suspicions of 
poorly hardened or of abnormally developed material, in so far 
as they justify any judgment, to the same extent as did the 
woodcuts accompanying his preliminary note. But the results 
of photographing with high powers are utterly inadequate to 
the preservation of the finer details of a preparation. It is 
doubtful if any preparation of a plant-tissue has yet been made 
in which the centrospheres were sufficiently distinct to be 
sharply brought out in a photograph. Our chief dependence 
must still be on the camera lucida and the pencil. Those 
of Farmer’s figures which are reproduced from drawings show 
none of the abnormal spindles which he describes. In view of 
the very remarkable agreement in the phenomena of nuclear 
division in the vascular plants in which it has been studied, 
one might almost feel justified in doubting the normal 
character of the phenomena described by Farmer for Lilium , 
because of their divergence from what occurs in Psilotum and 
Osmunda , as Farmer intimates I have done. But this would 
not be fair, especially when a proper basis for judgment is at 
hand. Unfortunately my own acquaintance with the cells 
studied by Farmer is very slight. This plant, however, has 
been a very favourite object for the study of karyokinesis with 
various other observers of the first rank. It is chiefly because 
of their difference in important respects from the observations 
of Strasburger, Guignard, and others, that I still venture to 
doubt that the phenomena described by Farmer are typical 
