286 CYTOLOGISCHE STUDIEN. 



such a far-reaching theoretical importance (one which admits the 

 existence in plants of a reducing division) as a mere appendage to 

 an interesting and important paper. 



The observations of Bronislaw Debski on nuclear division in the 

 CharacetB are of interest in relation to the systematic position of that 

 group. He finds that the form of karyokinesis agrees much more 

 closely with that of higher plants than with that of the alg;e. He 

 also states that no reduction of the number of chromosomes takes 

 place in the antheridia. This is very curious : a reduction must of 

 course occur, but where must remain a mystery until further work 

 has been undertaken. 



E. A. Harper's paper, ' Kerntheilung und freie Zellbildung im 

 Ascus,' consists of observations on nuclear division and cell formation 

 iu the ascus, chiefly of Enjsiphe. His most interesting results are 

 those on the relation of the nucleus and centrosome to the formation 

 of the wall of the ascospores, results which are in themselves quite 

 new, and have no doubt a far-reaching importance. 



Walter T. Swingle contributes observations on nuclear and cell 

 division in the SpJiacelariacew. Here for the first time we have a 

 thoroughly trustworthy account of the presence of centrosome and 

 radiations in connection with the resting nucleus. 



The last special paper in these studies consists of observations 

 by Prof. Strasburger on nuclear division and fertilization in Fncxis. 

 Some of these observations overlap those of Farmer and Williams ; 

 it is a curious fact that no one should have hitherto investigated in 

 detail the fertilization of Fiiciis, as it is an object which is peculiarly 

 favourable. He agrees with Farmer and Williams as to the point 

 of the life-history at which chromosome reduction takes place. 



The btudies end with some general conclusions by Prof. Stras- 

 burger on (1) the structure of cytoplasm, and nuclear and cell 

 division ; (2J on fertilization. These conclusions are for the most 

 part based on the observations published in the studies under con- 

 sideration, all of which show Strasburger's influence. A protest 

 must, however, be entered here on the way in Avhich the kinoplasm 

 theory is, so to speak, run to death by both Strasburger and his 

 pupils. Kinoplasm has in only one case been described in the 

 resting condition of the nucleus, and is usually completely invisible. 

 That kinoplasm and trophoplasm are convenient terms to describe 

 certain conditions of cytoplasmic difterentiation there is no doubt, 

 but that cytoplasm always consists of these two elements is a 

 totally different question, and one which rests on the flimsiest 

 foundation. 



Besides the papers mentioned above, there are observations of 

 H. 0. Juel on abnormal nuclear divisions in the pollen of llenwro- 

 callis fidni, and others of D. G. Fairchild on nuclear division and 

 fertilization in that curious fungus BasidiohuJus ramuum. 



These studies, taken together, are the most important contri- 

 butions to botanical cytology which have been published for a long 

 time. All honour is due to Prof. Strasburger for the power to 

 gather round himself a band of such enthusiastic and competent 

 workers. 



V. H. B. 



