200 



Journal of Applied Microscopy. 



only on a limited area of the auricle, 

 more to the left than right of the inter- 

 auricular wall. They were found in from 

 four to five large groups between which 

 lay scattered cells. The ganglion cell 

 groups were surrounded by connective 

 tissues and the cells separated from each 

 other by this substance. In addition to 

 the ganglion cells, there was on the sur- 

 face a large but variable number of cells 

 accompanying the nerves and vessels. 

 They can be distinguished from the 

 nerve cells by their deeper staining 

 powers and the absence of a capsule and 

 nuclear membrane. These cells have 

 been in earlier studies confused with 

 ganglion cells. 



Dr. P. Ris has an article on the struc- 

 ture of the optic lobes of the bird. This 

 is a very complete study of the different 

 layers of the lobes. Six distinct layers 

 were made out with subdivisions to some 

 of these. The author does not give any 

 definite answer to the question of contact 

 or continuity. 



Questions connected with the modern 

 Cell Problems have been well summarized 

 by Professor J. B. Farmer in "Nature." 

 The cell is discussed as a structural unit; 

 intercellular continuity of protoplasm, 

 interrelations of nucleus and cytoplasm, 

 and of the centrosome, phenomena of 

 nuclear division, and the problem of 

 reducing division, are all dealt with in a 

 manner giving a good summary of the 

 present situation of these questions. 



Dr. T. A. Henneguy gives in Ranvier's 

 new journal, " Archive d' Anatomic 

 microscopique," an interesting report on 

 some work done on the ciliated epithe- 

 lium of the gills of Lamellibranchs. From 

 his studies he concluded that the bases 

 of cilia react to stains exactly like centro- 

 somes, and considers them similar in 

 nature to those structures. 



In the same number of this new journal 

 is a most interesting summary of the 

 present status of knowledge of the origin 

 of the central corpuscle or centrosome in 

 fertilization. The author, D'Erlanger, 

 summarizes all the important contribu- 

 tions to knowledge on this subject, giving 

 in full, evidence for and against Pol's 

 theory of the quadrille of the centro- 

 somes. Evidence, he says, indicates most 

 strongly the origin of the centrosome; 

 of the first cleavage spindle from the 

 spermatozoon. Pol's theory has to be 

 definitely discarded for metazoans. For 

 Protozoans little can be said, as very lit- 

 tle work has been done in this line except 

 on a few infusorians. Several authors 

 have compared the micronucleus of the 

 protozoan with the centrosome and the 

 macronucleus with the nucleus of a 

 metazoan cell, but the researches on this 

 point are too few t.o determine the ques- 



tion. The author leaves the subject with 

 a reference to the need for further work, 

 both among plants and animals. 



In the last number of the "Zeitschrift 

 fur Wissenschafetiche Zoolgie," there is 

 an interesting article by R. Voltereck on 

 the development of the ostracod egg, sev- 

 eral species of Cypris being the forms 

 used. In oogenesis definite stages were 

 shown in the cells, a germinal zone and 

 zone of growth. In the zone of growth, 

 differentiation into egg cells and nutri- 

 tive cells takes place. The egg cells are 

 shown to possess yolk nuclei from the 

 beginning of their growth till just before 

 maturation takes place. Two polar 

 bodies are formed, although these are 

 parthenogenetic eggs. Cleavage is at 

 first holoblastic up to twenty-two cells, 

 after this it becomes more and more sup- 

 erficial and the blastoderm cells accumu- 

 late on the surface of the central inert 

 yolk, gradually losing their separate 

 identities, the cytoplasm becoming fused 

 to a continuous sheet. Among other 

 interesting points, the author notes the 

 formation of the tetrads by the chromo- 

 somes of the nutritive cells, although 

 these cells are destined to absorption by 

 the ova. Finally he speaks of the "yolk 

 nucleus," that much discussed and con- 

 fused structure. In Cypris the structure 

 is a true yolk nucleus having nothing to 

 do with the centrosome. It has, he 

 thinks, a direct connection with the 

 activity of the nucleus, as shown by its 

 position close to that part of the cell. 



The " Zeitschrift fur Mikroskopie and 

 fur Mikroskopische Technik" publishes 

 a note by Dr. Goncalves Cruz of Rio de 

 Janeiro, on a simple washing apparatus 

 for histological purposes. It is so simple 

 and effective for tissues that need pro- 

 longed washing that it is worth repeat- 

 ing. Two glass funnels, one larger than 

 the other, a graduate-shaped glass dish, 

 and a support with three adjustable 

 clamps, form the main features of the 

 apparatus. The smaller glass funnel is 

 inverted and connected with a water 

 pipe in such a way that a glass or metal 

 pipe may project downward beyond the 

 funnel to an amount nearly equal to the 

 depth of the glass dish next to be used. 

 This glass dish is placed below the in- 

 verted funnel and is of such a diameter 

 that the latter will rest just inside the 

 upper edge, and the space between 

 the two is so adjusted that 

 water will fiow out freely, but 

 pieces of tissue cannot.' The second 

 large funnel is placed erect below the 

 dish, receives the overflow of water, and 

 is connected with a waste pipe. The 

 three parts are clamped in position on a 

 vertical holder. The advantages of this 

 device are in its simplicity and the fact 



