2580 Journal of Applied Microscopy 



W 



CYTOLOGY, EMBRYOLOGY, 



AND 



MICROSCOPICAL METHODS. 



AGNES M. CLAYPOLE MOODY. 



Separates of Papers and Books on Animal Biology should be sent for Review to Agnes M. Claypole 

 Moody, 125 Belvedere Street, San Francisco, Cal. 



Nemiloff, Anton. Zur Frage der amitotischen The author limited his observations to 



Kernteiiung bei Wirbeltieren. Anat. Anz. vertebrate material and used for direct 

 23: 353-367, 1903. 



division, as most favorable objects, the 



giant cells of the epithelium of the bladder and the lymphoid layer of the liver 

 amphibia. In the first the object is very favorable, but shows no centrosome nor 

 attraction sphere. The second object is unfavorable owing to the comparatively 

 small size of the lymphoid cells; yet the relations of the central body to nuclear 

 division is very clear. 



The mouse was principally used for the giant cells of the bladder since the 

 giant cells are quite large, though thin. A chloroformed mouse was quickly 

 opened, the bladder cut lengthwise and fixed to cork with thin needles, with its 

 inner surface out. A cover-glass, cleaned with absolute alcohol and ether, is 

 quickly pressed on to the mucous surface. The epithelial cells stick to the sides 

 as in paraffin sections. The cover is put into fixatives after being fastened to a 

 piece of cork to keep it afioat. After fixation the cover can be treated in the 

 customary way. The stains used were Heidenhain's hematoxylin, saffranin 

 with light green or picric acid, toluidin blue with erythrosin. In cells so pre- 

 pared many division stages are found. In resting one or more nucleated cells 

 the nuclei are round or almost round, the nucleolus is in the middle, surrounded 

 by a light zone, the significance of which is puzzling. With the approach of 

 division the nucleus and nucleolus elongate ; the latter constricts in the middle 

 and finally divides into two spherical parts. The light zone divides after the 

 nucleolar process has ended. Nuclear division begins sometimes simultanously 

 with nucleolar division and sometimes after it is completed. It is a process of 

 constriction similar to that of the nucleolus. The two daughter nuclei are 

 spherical and somewhat flattened. Between the opposed surfaces of the nuclei 

 now appears a characteristic lining or striation of doubtful significance. This 

 internuclear substance stains with iron hematoxylin, but by prolonged bleaching 

 in alum becomes almost invisible, if slightly bleached it looks granular. It is not 

 possible that these appearances are artifacts, as they appear in some stages and 

 are absent from others on the same slide. The author sees a suggestion in this 

 of the processes of mitotic division. Preparations fixed in Lenhossek's mixture 

 and carefully stained with salifranin or iron hematoxylin show chromatin in 

 resting and dividing nuclei. Certain figures were found resembling Carney's 

 chromatic canals; these lengthening out on the division of the nucleus were re- 

 placed by the internuclear fibrous substance already spoken of. The lymphoid 

 cells of the liver of amphibians show three types of division, karyokinetic of the 

 typical kind, indirect, also the usual form, and a third of the following nature : 

 a funnel formed depression appears on one side. At the base of the depression 

 lies a granule that stains deeply, sometimes it is surrounded by radiating lines, 

 showing it to be a centrosome. These radiations are seen to connect with the 

 nuclear substance. This depression deepens until finally the nucleus is ring- 

 shaped with the centrosome in the middle. Gradually the ring thins at two 

 opposite points and two nuclei are formed, or there may be several. This forms 

 an intermediate type. a. c. m. 



