1884,] 



MICKOSCOPICAL JOUKNAL. 



127 



wire and driven into the board 

 after making holes with a small awl. 

 The paste- 

 board discs 

 are cut with 

 a steel punch 

 from board 

 havi n g a 

 thickne ss 

 of about an 

 eighth o f 

 an inch. 

 To p ro - 

 duce a neat 

 appearance 

 the board 

 should be 

 covered 

 w^ i t h a 

 sheet of 

 green or 

 other col- 

 ored paper 

 before cutting the discs. The trays 

 should be of soft wood about one- 

 fourth inch thick, with a piece 

 across the ends to prevent warping. 

 They may be made of any convenient 

 size. In the placing of the tacks and 

 discs it will be found necessary to use 

 a form in order to insure regularity. 

 The method of removing the slides is 

 by tilting them with the finger. 



The advantages claimed for a cab- 

 inet constructed on this plan are, 

 briefly, the following : The little lost 

 space and the securitv each slide has 

 w^hen in place from shucking or rub- 

 bing on its lower surface, the facility 

 with which a slide may be removed 

 or replaced, and the ease with which 

 the trays may be cleaned from dust. 



Albany, N. Y. 



Fig. 23. 



Celloidin for Imljeddiiig. 



[Celloidin is a material which 

 promises to be largely used in micro- 

 scopical work. We have not yet 

 been able to try it, but will do so be- 

 fore long, as it seems well adapted to 

 some work in which w^e shall soon be 

 engaged. It will be seen from our 

 advertising pages that it can be ob- 



tained from the agents, Messrs. Bach- 

 rach & Bro., in Baltimore. The two 

 following communications are copied 

 from the New York Medical Jour- 

 7ial^ in which they first appeared. — 

 Ed.] 



Celloidin was first introduced into 

 histological technique by Schiefter- 

 decker, {^Arch. f. Anat. ti. Phys., 

 1882, pp. 199-203,) and has met 

 with general favor. It is a pure py- 

 roxlin, free from all foreign organic 

 constituents, and makes a clear solu- 

 tion free from sediment. It is solu- 

 ble in equal volumes of alcohol and 

 ether, and the degree of concentra- 

 tion may be varied to suit any par- 

 ticular case. 



The following is the manner of 

 preparing and using the material, as 

 practiced in the laboratory of the 

 Alumni Association of the College of 

 Physicians and Surgeons : A satura- 

 ted solution of celloidin is made in a 

 mixture of equal parts of ether and 

 alcohol (97 per cent.); this requires 

 about twenty-four hours, with occa- 

 sional agitation. The specimen to 

 be imbedded is soaked in a mixture 

 of ether and alcohol for some time, 

 then transferred to the imbedding 

 fluid and allowed to remain over 

 night. 



One of two ways of imbedding 

 may be adopted : 



1. Cover the smooth surface of a 

 cork with a thick layer of celloidin 

 solution and allow it to dry ; place 

 the specimen, which had previously 

 been soaked in the imbedding fluid, 

 on this, and cover it, layer by layer, 

 with a solution of celloidin, allowing 

 each layer to partially dry before ap- 

 plying another. When the specimen 

 is completely covered, immerse in al- 

 cohol of 80 per cent, for twenty-four 

 hours, when it will be ready to cut. 



2. The specimens are imbedded in 

 paper boxes in the usual way, or a 

 cork is wrapped with one or two 

 layers of thick writing paper, allow- 

 ing it to project an inch or an inch 

 and a half above the surface of the 

 cork. By this procedure a round 



