. Carnegie Institution of Washington publication. REACTION OF THE PLANT. 93 an enlargement of the nucleus, often to double the normal size, and often a change of shape to spindle form. In such tissues the nuclei stand out very prominently in the small cells, being the most conspicuous objects in the section. This size, however, may be a character- istic of extreme youth rather than of disease, since the writer has also seen large nuclei in the tissues of the growing point of healthy daisy-plants. The disorganization of the nucleus in root-nodules of Leguminosae seems to be preceded by some enl
. Carnegie Institution of Washington publication. REACTION OF THE PLANT. 93 an enlargement of the nucleus, often to double the normal size, and often a change of shape to spindle form. In such tissues the nuclei stand out very prominently in the small cells, being the most conspicuous objects in the section. This size, however, may be a character- istic of extreme youth rather than of disease, since the writer has also seen large nuclei in the tissues of the growing point of healthy daisy-plants. The disorganization of the nucleus in root-nodules of Leguminosae seems to be preceded by some enlargement. The subject requires further study. CHANGES IN THE CHROMOSOMES. Following Farmer's statements and similar statements by other English students of malig- nant animal tumors, the writer has been very much interested to see whether the chromosomes undergo any change in number or location in the rapidly dividing cells of crown-galls and similar plant tumors. The first studies were made on peach tissues but here the nuclei are so small that the determination of the normal number of chromosomes proved difficult. At- tempts to get tumors on onion, the normal cytology of which is well known, also failed. The Paris daisy was finally selected. This has large nuclei and the normal number of chro- mosomes appears to be 16. A study of slides prepared from very young stages of tumors taken from this plant has thus far shown noth- ing definite except that at least a part of the divisions are mitotic. The most interesting thing made out in connection with the cell morphology is that first pointed out by Tourney for the almond gall, viz., the occurrence of more than one nucleus in a cell without any evidence of the beginnings of a cell-wall between them. Toumey figures 2,3, and 4 nuclei in a cell. The writer has seen two well-developed ones in cells of the rose gall. ANTIBODIES. This is almost a wholly unworked field. Fig. 29.* The writer has seen nothing corresponding to the self-lim
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