Journal of Applied Microscopy. 



403 



lines may be scratched on the glass, if desired. The same mixture serves as an 

 imbedding medium. The collodion plate containing the oriented specimen is 

 carried into xylol for a short time, then left in paraffin for about five minutes, 

 until the xylol adhering to the glass is absorbed. 



For specially difficult orientation the specimen may be placed in clove oil 

 and collodion under a cover-glass, with two thin tubes for rollers, and rolled into 

 position. A drop of ether will thin the medium, which may then be left to reach 

 such a consistency that the object cannot be turned, before placing in paraffin. 

 Sections may be cut four or five /,< thick. 



The method is valuable for small objects and for objects that are not easily 

 penetrated by paraffin, or that would be injured by heat, or where there is much 

 yolk or albumen and the specimen is liable to crumble when sectioned. 



E. M. Brace. 



Stokes, Dr. Alfred C. Fresh-Water Infusoria. The life cycle of the infusoria is de- 

 Pop. Sc. 33: II0-II2, i8qq. -i i i ._i i • ^- i 

 ^ scribed, and there are descriptions and 



illustrations of several forms, with directions for collecting them. In examining 



them, the writer uses a simple life-slide, which consists of a shallow cell made 



of shellac, with two opposite portions scraped away to admit the air, and covered 



with a square cover-glass (Fig. 1). A modification of Logan's life-box (Fig. 2) 



-Lite-cell. 



Life-box. 



is made by cementing a small cube of glass to a slide with Canada balsam. 

 This cube is surrounded with a thick glass or zinc ring having a layer of wax on 

 it to which a cover-glass is cemented by running a hot needle around the edge. 

 The life-box should be air-tight to prevent the evaporation of the drop of water 

 containing infusoria, which is placed on the central cube. E. M. Brace. 



Lecaillon, A. Recherches sur I'oeuf et sur le The author has studied six of the 



developpement embryonaire de quelques , i- i <". i • , ^ 



Chrysomelides. Theses presentees a la chrysomelldae, Cytra laeviUSCula, Gas- 



Faculte des Sciences de Paris. Ser A. No. trophysa raphani, Chrysomela menta- 



299, I-2I9, 4 pis., 2 figs., 1898. 4.-T- l-Ti. 1 JAl 



stri, Lina populi, L. tremulae, and Agel- 

 astica alni. It seems there is no chitin present in the envelopes of these eggs, 

 and segmentation is of the typical, superficial form usual to insect eggs. The 

 author objects, however, and very wisely, to the term " superficial," and suggests 

 " intravitelline " as more descriptive of the process, since the egg nucleus 

 segments in the middle of the egg and the nuclei move outward through the yolk 

 mass afterwards. Those reaching the surface form ectoderm, while those 

 remaining behind are to produce entoderm. Mesoderm rises from the ectoderm, 

 and is very variable in its manner of appearance. Sex cells arise very early and 

 are ectodermic, while the whole alimentary tract is formed from the proctodaeum 



