182 The Microscope. 



■with the present elegant, and, we might say scientific, methods of 

 attaining the same end. 



It is true that Bunge had pubHshed his egg-emulsion method, 

 modified by Calberla as long ago as 1876, but, however well adapted 

 to certain tissues and objects it may be, it could never become of uni- 

 versal service. No wonder then, when Schiefferdecker announced, 

 in 1882, his modification of D uvall's discovery of a new substance of 

 general use as an embedding material, that this was hailed with delight 

 by all biological investigators. But, although celloidine has now been 

 before microscopists for fully six years, and articles on its use have 

 frequently appeared in our scientific journals and text-books, there 

 still seems to be a profound ignorance on the part of some as to its 

 successful employment. Our experience, dating from the time 

 of Schiefferdecker's first article on the subject, has taught us that for 

 embedding tissues having a loose meth, there is no material belter 

 than celloidine. The main points in its use are, a properly hardened 

 object soaked for several hours in equal parts of ether and absolute 

 alcohol, then transferred for twenty-four hours to a thin solution of 

 celloidine, and afterwards placed for several hours in a molasses- 

 thick solution of this material, when it may be embedded on a cork 

 or left indefinitely in the fluid. 



Various modes for the successful employment of paraffin are 

 constantly coming to the fi'ont, but none will be found of greater 

 service than the excellent method proposed by Dr. Minot in our last 

 issue. This, as the writer says, is sifted from the great mass of 

 literature on this subject, and contains the essence of the best forms. 



But, according to certain investigators, the use of either celloidine 

 or paraffin alone has disadvantages which are only overcome when 

 the two materials are properly combined. Kultschizky {Zeitsch.f. Wiss. 

 Mikr.), an advocate of this method, places the hardened object for 

 some hours in equal parts of ether and alcohol, then in a solution of 

 celloidine for twenty-four hours, then in erigeron oil, erigeron oil^ 

 and paraffin heated to 40° C, and finally in melted paraffin. The 

 time which the object must remain in the oil, the oil and paraffin 

 and the melted paraffin, can be determined only by trial and a * 

 knowledge of the structure of object to be embedded. Sections are 

 cut dry, as in the simple paraffin method. 



Much has of late been written in regard to the advantages offered 

 by vegetable wax as an embedding substance, but from Francotti's 

 careful experiments we learn that this material is much inferior to 

 paraffin for this purpose. This writer finds that the best results 



