380 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Demonstrating the Structure of Mollusca.* — R. Anthony, in his 

 study on the morphology of the acephalous Mollusca, made casts of the 

 shells and of the palleal cavity by means of plaster, wax, or gelatin. For 

 obtaining a cast of the cavity, two holes were made in the shell, and the 

 plaster poured in through one hole by the aid of a funnel. 



The mould set in a few hours, and then the shell and soft parts were 

 removed, sometimes with the aid of acid. 



Fixation was effected in a mixture of formalin 4 and alcohol (70 p.c.) 

 100. The material was imbedded in paraffin or collodion. Staining 

 was sometimes effected en masse, at other times in sections. The usual 

 tinctorial solutions were employed. Teasing out the muscle and dis- 

 sociation were found to give better and more instructive results than 

 sections. 20 p.c. nitric acid, allowed to act for 12-24 hours, was used. 



For luting down the preparations, caoutchouc dissolved in benzin 

 or sulphide of carbon was used. The caoutchouc dissolved in benzin 

 was found to be specially useful for fixing up preparations mounted in 

 aqueous media. 



Marking* the Directing* Plane on Blocks for Reconstruction.! — 

 K. Peter finds that Nubian waterproof blacking makes an excellent over- 

 lay for marking out the directing plane of blocks used for reconstruction 

 models. The embryo is first imbedded in paraffin, and then the blacking 

 is painted on with a brush. In a few minutes the surface dries, and 

 then the block is covered with another layer of paraffin. It is equally 

 suitable for paraffin and celloidin imbedding, and is applicable to all the 

 usual procedures. 



I ,; (4) Staining- and Injecting'. 



Demonstrating the Presence of Spirochaeta pallida.} — E. Bertarelli 

 and G-. Volpino adopt the following method for staining Spirochceta 

 pallida in tissues. Very small pieces, 0*6 to 0*7 mm. thick, are fixed in 

 alcohol. They are then immersed in the silver solution for 3-4 days 

 (silver nitrate 1*5, distilled water 50, alcohol (96 p.c.) 50, glacial acetic 

 acid 4-5 drops). This fluid must be renewed as soon as a precipitate 

 forms. The pieces are then frequently washed in distilled water, after 

 which they are placed for 24 hours at room temperature in Van Erinen- 

 geum's reducing medium (tannin 3, gallic acid 5, sodium acetate 10, 

 distilled water 350). This fluid must be changed as soon as it becomes 

 cloudy. After a thorough wash in water the material is passed through 

 alcohol chloroform to paraffin. The sections should be from * 3 to • 7 fj. 

 thick. 



Simplified Method of Staining Blood Films. § — R. Lenzmann 

 stains air-dried blood films by the following method. Solution 1 con- 

 sists of eosin 1*2, absolute alcohol 100, formol 5, sublimate 0*3 ; filter. 

 To 10 c.cm. of this solution is added 1 c.cm. of the following methylen- 

 blue solution : methylen-blue 0*8, absolute alcohol 100, 3 p.c. acetic 



* Ann. Sci. Nat. Zool,, ser. 9, i. (1905) pp. 165-396 (57 figs, and 3 pis.). 



t Zeitschr. wiss. Mikrosk., xxii. (1905) pp. 530-8 (2 pis.). 



% Centralbl. Bakt., lte Abt. Orig., xli. (1905) pp. 74-8 (1 pi.). 



§ Zeitschr. wiss. Mikrosk., xxii. (1905) pp. 431-3. 



