ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 233 



I>Lei-ally, unitcii by fine threads with one another, and with the 

 more internal granules, the knots of the network, so that the central 

 nucleolus is woven round on all sides. In the nuclei of the larva 

 and imago of Tenehrio, a crystal-like body is present — a phenomenon 

 in animal histology which was till lately unique. In the larvfe of 

 Muscidfe the typical network is absent, and the roll-of-money-like 

 nuclear bands are observed. In caterpillars, and probably in all 

 Hymenopteran larvje, the nucleus appears as a vesicle, containing 

 a homogeneous fluid, in which true nucleoli, nucleolids, and minute 

 granules are imbedded. Fine processes are observed passing from 

 the nucJeoUd bodies, which are therefore perhaps united in a sort of 

 network. The minute granules are all of the same size, and are 

 perfectly spherical and free, and when they are retracted from the 

 periphery of the nucleus, a pale loose network is sometimes revealed. 



The regeneration of the cells. — In continuation of his former 

 research on the epithelial regeneration in Crustacea, Dr. Frenzel 

 describes that in the mid-gut of insects. The epithelial cells, whether 

 " cylindrical " or " mucous," both in the canal itself and in its 

 diverticula, reproduce themselves by direct (" amitotische ") division, 

 while the specifically glandular cells of the crypts exhibit in their 

 division karyolytic phenomena. The prevalence — indeed the pre- 

 dominance — of the direct method of division in epithelial cells is 

 maintained, and the extreme position which denies its existence is 

 criticized. 



The physiological import of the cells. — After pointing out that 

 the main work of digestion must be discharged by tlie mid-gut, and 

 that in the absence of pseudopodic processes, intracellular digestion 

 is out of the question, the author maintains that in most cases, at 

 least, the whole epithelial cell perishes in discharging its secreted 

 substance. Except in some cases where the secreted matenal is not so 

 abundant, or definitely and firmly former!, and where consequently 

 the substance might be discharged and replaced piece-meal, the 

 sacrifice of the whole cell seems the only alternative. The opinion 

 that the " secreted substance " might be the result of absorption is 

 sharply criticized. The problem of absorption is discussed, but in 

 face of such difiiculties as that of ascribing the absorptive function 

 at once to mid-gut and hind-gut, Dr. Frenzel prefers to confess the 

 absence of any definite knowledge of the process. He maintains the 

 absence of liver-like organ or bile-like secretion. 



Bees and Bee-keeping.*— Mr. F. E. Cheshire, whose researches 

 on bees and their diseases are so well known to the Fellows of the 

 Society, has embodied the results of his investigations in a book 

 which cannot fail to be highly appreciated by all naturalists who 

 are iuterested in bees, and even more so by those who regard bees less 

 from their scientific than from their commercial aspect. 



The fii-st volume now issued deals with the scientific part of the 

 subject, and is intended to be followed by a second '• practical " 



* Clic-hiie, F. R., ' Bees ntid Bee-kecpiug, Scientific and Practical,' vol. i. 

 Scientific, 336 pp., 8 pis. auil 71 figs. 8vo, Loudon (L. Ui;cott Gill), ISSt). 



