ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 685 



chromosomes, each of which is composed of two longitudinal halves. 

 The chromosomes take up their definite form, not in consequence of :u 

 folding on themselves, hut as the result of hecoming shorter and thicker. 

 They do not curve when they approach the spindle, but become attached 

 at a point most often near one of their ends. They insert themselves 

 into the spindle in such away that the daughter-chromosomes are placed 

 upon one another in the axial plane. Before the separation of the equa- 

 torial plate the daughter-chromosomes undergo a fresh longitudinal divi- 

 sion, in consequence of which they assume the V-form in which they retreat, 

 towards the poles. This second longitudinal division is often completed 

 during the return to the poles. The daughter-chromosomes of the first 

 karyokinesis preserve their individuality in the reconstituted nucleus. 

 They reappear with their characteristic V-form at the beginning of the 

 second karyokinesis. These V-formed bodies, without undergoing any 

 further longitudinal division, furnish, by separation at their angles, the 

 •laughter-chromosomes of the second karyokinesis. 



Development of the Karyokinetic Spindle in the Pollen-mother- 

 cells of Cobaea scandens.* — Mr. Anstrnthcr A. Lawson gives the follow- 

 ing summary of observations made by him on this process. In the 

 cytoplasm, which assumes a distinctly reticulate structure, two con- 

 stituents may be distinguished — a filamentous part which forms the 

 framework of the reticulation, and a granular portion which collects 

 round the nucleus as a complete zone, and to which the author gives the 

 name Perilcaryoplasm. When the nuclear membrane bursts, the lining 

 of the nucleus and the perikaryoplasm form a network which occupies 

 the central portion of the cell. This network increases, extending in» 

 several directions so as to form the cones of the multipolar figures. 

 The fibres of the spindle are formed by the lengthening of the meshes 

 of the network in the direction of the extensions. The cones lengthen' 

 and become sharply pointed ; they separate into two groups, and form 

 the bipolar spindle. The mature spindle is characterised by its great 

 length and by the intercrossing of the fibres of its mantle. The spindle 

 of the second division is formed in precisely the same way as that of 

 the first division. No structures which could be identified with centre - 

 oomes w r ere detected in any stage of the karyokinetic process, 



(2) Other Cell-contents (including 1 Secretions). 



Proteids of Plants.f — Researches made by T. B. Osborne and G. F. 

 Campbell show that the leguminous plants examined — pea, beau, lentil, 

 vetch — all contain legumin, legumelin, and proteose, and the first three 

 also vicilin. Globulin is the most frequent proteinaceous constituent of 

 the seeds. Vicilin is most abundant in the lentil, least so in the bean. 

 It is apparently not a product of legumin, since the seeds of vetches do- 

 not contain any. Legumelin is probably an albumin. It was found in all 

 leguminous seeds examined except Phaseolus vulgaris and the blue and 

 yellow lupins. The most abundant proteid in the bean is glycinin, a 

 globulin closely resembling legumin in its properties, but containing, 

 twice as much sulphur. 



* Proc. California Acad. Sci., i. See Bull. Soc. Bot. Ital.. 1900, p. 177. 

 t Journ. Anier. Chem. Soc, xx. pp. 393 and 419. See Bot, Ceutralb!., lxxxiii. 

 (1900) p. 324. 



Dec. 19th, 1900 3 a 





