ZOOLOGY AND BOTANY, MIOKOSCOPY, ETC, 667 



being heated for a sufficiently long time, the cover-glass is placed on, and 

 the alga, which was previously dry and shrunk, is now found to have 

 swollen up to its natural form. The cell-contents are at least partially 

 dissolved or clarified if the preparation has been boiled sufficiently long, 

 a point of great importance, especially in the examination of desmids. 



Tempere's Preparations of Diatoms.* — M. J. Tempere is preparing 

 series of all the known genera of diatoms. Each series will comprise 

 twenty-five preparations, and each preparation will contain one to three 

 species or varieties. The first series has recently appeared. 



Feeeborn, G. C. — Notices of new Methods. III., IV. 



[Sublimate as a hardening medium for the brain (Diomidoff). New methods 

 of preparing nerve-cells (Thanhoifer). Neutral anilin staining fluid (Babes). 

 Safrania solution with anilin oil (Babes). 



Ajner. Mon. Micr. Journ., IX. (18S8) pp. 84, 111-2. 

 Lugger, O. — A new Method of Preserving transparent Aquatic Insects for the 

 Microscope. Proc. Entorn. Soc. Washington, I. (1888) pp. 101-2. 



Ma NT ON, W. P. — Endiments of Practical Embryology. III. 

 [Preparation of the Embryo. Hardening.] 



Uie Microscope, VIII. (1888) pp. 144-5. 

 Pelletan, J. — Les Diatomees, histoire naturelle, preparation, classification et 

 description des principales especes, avec une introduction a I'etude des diatomees 

 par M. J. Dehy et un chapitre sur la classification des diatomees par M. Paul Petit. 

 (The DiatomacesB, natural history, preparation, classification and description of 

 the principal species, with an introduction on the study of the Diatomacese by 

 M. J. Deby, and a chapter on classification by M. Paul Petit.) 

 [Contains chapters on collecting, preparing and mounting.] 



vol. i., 350 pp., 5 pis. and 250 figs., 8vo, Paris, 1888. 



(3) Cutting:, including^ Imbedding-. 



Collodion for Imbedding in Embryology.t— In a note appended to 

 a paper on " Collodion in the Technique of Embryology," Prof. M. Duval 

 states that celloidin has no advantage over collodion ; with thick collodion 

 the same hard and resisting mass is produced, and this is always quite 

 transparent, which is not the case with celloidin. 



The method given for imbedding in collodion is as follows : — When the 

 piece is removed from spirit after having been hardened, it is placed for 

 some short time in a mixture of alcohol and ether (1 spirit, 10 ether). It 

 is then placed in a solution of pure collodion for 10 minutes to 24 hours, 

 according to size, after which it is immersed in a solution of collodion 

 of a syrupy or pasty consistence, according to the degree of hardness 

 required for the imbedding mass. On removal the mass is exposed to 

 the air for not more than a minute, and it is then plunged into alcohol 

 of 36° ; the vessel containing the spirit is left open. In 6 to 10 hours 

 the collodion is sufficiently solidified, and transparent as glass. The 

 mass is then stuck on a piece of elder-pith with collodion, and fixed 

 then in any position for cutting sections, which are made with a wet 

 knife. Under certain circumstances, as, for example, when it is desired 

 to obtain sections of batrachian ova, which are extremely friable, it is 

 necessary to smear the surface of every section with collodion, in order 

 to prevent the sections breaking up or evacuating their contents. The 

 collodion for this purpose is made very thin, and a few minutes after it 



* Journ. de Microgr., xii. (1888) pp. 226-7. 

 t Ibid., pp. 197-204. 



