436 



SCIENCE 



[N. S. Vol. XXXI. No. 794 



that the hybrids of these cultures carried in 

 marked preponderance the paternal characters 

 (patroelinous), or, on the other hand, that ma- 

 ternal characters -were more prominent. The 

 range of variation among the hybrids was too 

 great to permit of such conclusions. 

 The Effect of Some Toxic Solutions on Mitosis in 

 Yicia fata: W. W. Stockbekgeb, Bureau of 

 Plant Industry, U. S. Department of Agricul- 

 ture. 



Root-tips of Vicia faba were exposed for varying 

 lengths of time to the action of very dilute and to 

 more concentrated solutions of copper sulphate, 

 phenol and strychnine. As a result the achro- 

 matic figure was frequently enlarged and the 

 spindle seemed to increase in size. Later the 

 spindle fibers were more seriously affected, be- 

 coming disorganized, while numerous vacuoles 

 formed in the cytoplasm. Mitosis was interrupted, 

 but without deformation of the chromatic figure. 

 Formation of the cell plate was often prevented, 

 following which, however, complete reconstitution 

 of the nuclei was not observed. Neither the 

 binucleate cells nor the nuclear fusions of some 

 authors occurred in the material studied. No 

 amitosis was observed and there was no evidence 

 that it is produced by these solutions. The inter- 

 pretation as departures from the normal due to 

 the toxic solution of the numerous aberrant forms 

 which occurred in the toxicated material was 

 negatived by the occurrence of similar forms in 

 the controls. Material grown in distilled water 

 was affected in much the same manner as that in 

 the toxic solutions. When toxic salts were used 

 in great dilutions it became very difficult to dis- 

 tinguish between their effect and the physical 

 action of the solution in which they were dissolved. 

 Nuclear Organisation in the Conidia of Sphwro- 

 theoa: E. H. Hakpee, University of Wisconsin. 

 Polarized nuclei with a central body in perma- 

 nent connection with the nuclear chromatin and 

 similar in all respects to those described for the 

 ascocarp and mycelium of Phyllactinia are found 

 also in all stages of the development of the conidia 

 of the Sphcerotheca on Bidens. 



The resting stages are of especial importance, 

 as it is at this time that the connection of centro- 

 somes and chromatin is of especial significance 

 as giving evidence of the permanence of the chro- 

 mosomes as definitely organized bodies. 



The center in these conidial nuclei is disk- 

 shaped and lies on the outside of the nuclear 

 membrane. Cases in which the center is pulled 



into the cavity of the nucleus are found, but are 

 plainly artefacts due to fixation, as are probably 

 also the similar cases figured by Maire and Guil- 

 liermond. The chromatin in the resting condition, 

 may appear almost homogeneous and evenly dis- 

 tributed in the nuclear cavities, but even here a 

 few strands show the special connection of the 

 mass with the central body. 



In the prophases the granular material becomes 

 gradually aggregated in strands which show a 

 definite orientation toward the central body. The 

 gradual differentiation of a spirem can be traced 

 in all its stages and the heavy strands finally 

 formed are always attached at one end to the 

 center. Throughout the resting stage and pro- 

 phases organic connection is maintained between 

 the central body and chromatin and thus a mech- 

 anism is provided for the maintenance of the 

 individuality of the chromosomes through the 

 processes of splitting in nuclear division and of 

 fusion in pairs side by side in fertilization. The 

 spindle formation follows the usual type which I 

 have described for the nuclei of the ascus. 

 Nuclear Phenomena in Lachnea scutellata: Will- 

 iam H. Bbown, Johns Hopkins University. By 



invitation. 



The asci of Lachnea scutellata arise from a one- 

 celled ascogonium at the base of the fruit-body. 

 No antheridium has been observed and no fusion 

 or pairing of nuclei in the ascogonium or young 

 ascogenous hyphse. The nuclei of the vegetative 

 hyphiE, ascogonium and ascogenous hyphae show 

 five chromosomes. During prophase these chro- 

 mosomes may be close together and resemble a 

 second nucleolus. In reorganizing, the daughter- 

 nuclei are often so close together as to appear to 

 be fusing. These two phenomena may have been 

 mistaken by some for fusing nuclei. 



The usual hooks are formed at the ends of the 

 ascogenous hyphae. The two nuclei of the penul- 

 timate cell may fuse and give rise to the nucleus 

 of an ascus, or they may not, in which case a 

 second hook is formed. An opening is formed 

 between the ultimate and penultimate cells and 

 the nucleus of the penultimate migrates into the 

 ultimate, which may then form a second ascus or 

 another hook. This process may be repeated many 

 times. 



The first division of the nucleus of the ascus is 

 the reducing division and shows the usual hetero- 

 typic prophases. It is the only division that 

 shows the diploid number of chromosomes. 



The spore wall is laid down near the outer 



