ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1 3 



Division of the Nucleus in Vegetative Cell?.* — Prof. D. M. Mottier 

 states that, in the process of karyokinesis in the vegetative cells of 

 Lillum, during the formation of the spindle, the kinoplasm is present 

 in a much smaller quantity than in the sexual cells of the same plant- 

 As a rule, it is not at first arranged radially about the nucleus, but 

 forms a delicate weft which may be closely applied to the nuclear 

 membrane. The kinoplastic fibres of the weft form a multipolar 

 spindle which is readily transformed into the ordinary bipolar type. 

 These accumulations of kinoplastic fibres are characteristic of a definite 

 phase in the development of the spindle in certain vegetable cells. 

 The author considers that the development of the karyokinetic spindle 

 proves conclusively that centrosomes do not exist in the higher plants. 



Fusion of Nuclei.j — Mr. P. Groom reviews the recorded cases of 

 a non-sexual union of nuclei in Fungi, Florideas, and Phanerogams, and 

 suggests the following hypothesis : —The nuclear union does not, in 

 these cases, represent a true sexual act ; it is an interpolation. It takes 

 place in a small generation which is fructificative in development. 

 The generation in which the nuclear fusion occurs is probably in all 

 cases degenerate ; and it is natural to suppose that the fusion is corre- 

 lated with the vegetative degeneracy. The theory that the object of 

 the nuelear union is to double the chromosomes is negatived by the 

 occurrence of a double union in the Ascomycetes, and by the fact that 

 in Angiosperms tho chromosomes in the endosperm sometimes preserve 

 the half number. For these pseudo-sexual unions the author proposes- 

 the term " deuterogamy." 



Dependence of the Streaming- of Protoplasm and the Movements 

 of Vibratile Cilia on Free Oxygen.} — Herr G. Eitter records the 

 results of a series of experiments for determining this question, made 

 mostly on aerobic and anaerobic bacteria and on the movements cf 

 protoplasm in Chara and Nitella. The following are some of the chief 

 results reached. With the facultative anaerobic bacteria, the duration 

 of the anaerobic movements depends greatly on the nature of the nutri- 

 tive medium, lasting from three to seven times as long with some as with 

 others. The absence of oxygen has a tendency to produce motionless 

 rather than motile forms. In the Characeaa the experiments determined 

 also the capacity for anaerobic existence, and even growth, to a limited 

 extent. The author concludes that the intramolecular respiration, and 

 in consequence the anaerobic movements of protoplasm, in Nitella, are 

 not dependent on stored-up oxygen, any more than are the ordinary 

 phenomena of life. The difference between chlorophyllous and non- 

 chlorophyllous temporary anaerobes consists in this : — that the former 

 can themselves manufacture their food-materials out of inorganic sub- 

 stances, with the help of the solar energy ; while the latter are dependent 

 on already organised nutrient substances. 



Effect of Centrifugal Force on the Cell .§— Prof. David M. Mottier 

 records the result of a series of experiments on the effect on the struc- 



* Proc. Indiana Acad. Sci., 1898, pp. 164-6." 



t Trans, and Proc. Bot. Soc. Edinburgh, xxi. (1899) pp. 132-44. 



X Flora, Ixxxvi. (1899) pp. 329-60 (1 fig.). 



§ Ann. of Bot., xiii. (1899) pp. 325-62 (1 pi.). 



