ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 497 



ink, and then receive tAvo or three thin coats of celloidin. In order to 

 remove a series from the paper strips, it is only necessary to immerse the 

 section in water, when it floats away to the top, and may then be lifted 

 on to the prepared slide, which nnist previously be moistened with 

 distilled water. When all the sections are arranged, the excess of water 

 is poured or blotted off, and then with two or four folded strips of 

 paper the sections are firmly pressed down into the celloidin layer on the 

 slide. To insure firm adhesion, the slide is dipped in alcohols upgraded 

 from HO p.c. to 98 p.c, and on removal the sections are smoothed down 

 each time. Lastly, a little ether is brushed over the surface. After a 

 partial drying, the' slides may be stained right away, or preserved for 

 future use in 80 p.c. alcohol. 



The adhesion of the sections to the slide is so firm that they can be 

 stained with hematoxylin, decolorised with hydrochloric-acid-alcoliol, 

 and neutralised with ammonia water without the film stripping off, 

 though care must be taken not to make the changes from alcohol to 

 water too sudden, nor should absolute alcohol be used too long for 

 dehydrating. For clearing up, carbol-xylol answers well. About 10 

 troughs, 12" by 6 by 4 cm.,"are required for the different fluids. For 

 accurately disposing of the sections on the slide, the author uses a piece 

 of card or glass some 3 by 2 in., with vertical and transverse lines ; this 

 is placed under the slide while arranging the sections. 



(4) [Staining and Injecting-. 



New Modification of Romanowsky's Stain.* — R. May has devised 

 the following simple method of applying Romanowsky's stain. The 

 preparation is stained in a 0*25 p.c. methyl-alcoholic solution of acid 

 eosin-methylen-blue, and placed for one minute in distilled water ; then, 

 whilst still wet, a drop of 0-5 p.c. methylen-azur solution distributed 

 regularly over the specimen ; by the action of the methylen-azur the 

 blue nuclear stain is faded and assumes a red appearance. 



The method is suitable for staining bacteria and spirochastes. 



Studying Oogenesis in Paludina vivipara and Chromidia in 

 Paludina and Helix. + — M. Popoff fixed the material, ovaries of animals 

 at different ages obtained in spring, summer and autumn so as to get all 

 stages of development, in Zenker's, Petrunkewitsch's and in Flemming's 

 fluids. Flemming gave excellent results for nuclei in Paludina, but 

 blackened the cytoplasm too much ; on the other hand, for Helix it was 

 specially good. The preparations were stained with iron-haimatoxyhn, 

 but for deciding the case of the nucleolus they were controlled with 

 Delafield's hematoxylin, hematoxylin-eosin, hematoxylin-acid-fuchsin, 

 Flemming's double stain, Berlin V)lue, borax-carmin, and gentian-violet. 

 Teased-out preparations stained with borax-carmin and examined in oil 

 of cloves were of great service. 



* Centralbl. Bakt. Eef., Ite Abt., xxxix, (1907) p. 582. 



t Archiv Mikrosk. Anat. u. Entwickl., Ixx. (1907) pp. 43-129 (5 pis.). 



