128 



THE AMEEICAN MONTHLY 



[July, 



box, with the cork for a bottom, is 

 obtained. Into this box pour a small 

 quantity of the imbedding fluid, and 

 allow it to dry. The specimen, hav- 

 ing been previously soaked in the cel- 

 loidin solution, is now placed in the 

 box, adjusted as to position, and al- 

 lowed to dry for five or ten minutes, 

 so as to fix it ; the box is now filled 

 with the imbedding fluid. The boxes 

 are exposed to the air until the im- 

 bedding mass has become semi-solid, 

 and are then immersed in weak alco- 

 hol (alcohol 95 per cent., two parts, 

 water one part) for twenty-four hours, 

 when the specimen w^ill be readv for 

 cutting. If the specimen has been 

 imbedded in a paper box and sections 

 are to be cut with a sliding micro- 

 tome, it is necessary to mount it on a 

 cork. This is accomplished in the 

 follow^ing manner : Cover the surface 

 of a smooth cork with a thick layer 

 of celloidin solution, allow it to dry, 

 and again cover w^ith the same. Trim 

 off' the superfluous imbedding mass 

 from around the specimen, cut the 

 lower surface even, wet it with a drop 

 or two of ether, and adapt it to the 

 layer of celloidin on the cork. Dry 

 for a few moments and place in dilute 

 alcohol for a few hours, when the 

 specimen will be ready for cutting. 

 If the plan of imbedding in the boxes 

 with a cork for the bottom is adopted, 

 the specimen is imbedded and mount- 

 ed on the cork at the same time. 



Sections may be stained with the 

 different staining ffuids and mounted 

 in glycerin or other media. If mount- 

 ed in Canada balsam, and the speci- 

 men is to be retained in the imbed- 

 ding mass, absolute alcohol for dehy- 

 drating and oil of cloves for clearing 

 are to be discarded, for they both dis- 

 solve the celloidin and alcohol of 96 

 per cent., and oil of bergamot, oil of 

 Sanders, or oil of origanum used. 



Celloidin is manufactui'ed by E. 

 Schering, of Berlin, and may be ob- 

 tained of Bachrach & Brother, Balti- 

 more, Md. It comes in the form of 

 gelatin plates and shreds, put up in 

 ounce packages. The shreds are to 



be preferred on account of being more 

 easily dissolved. 



G. C. Freeborn, M. D. 

 At the laboratory of the New York 

 Hospital the following method is em- 

 ployed in imbedding objects in cel- 

 loidin : The celloidin, which is a 

 hard, semi-transparent, colorless ma- 

 terial, is cut into small pieces and dis- 

 solved in a mixture of equal parts of 

 absolute alcohol and ether until the 

 solution is of a thick, creamy con- 

 sistence. The solution should be 

 kept in a wide-mouthed bottle, closed 

 by a tight-fitting ground-glass stop- 

 per. The object to be imbedded is' 

 placed in absolute alcohol for two 

 days to remove all the water, then 

 for a day or two in ether, and is then 

 ready for imbedding. The object is 

 then placed in the celloidin, and left 

 there until it is thoroughly soaked 

 through by it. This lasts about four 

 days. When fine sections of delicate 

 tissues — as the lung, spleen, retina, 

 or testicle — are desired, it is better to 

 leave the object in for a week. After 

 removing the object from the celloi- 

 din, place it in ordinary alcohol for a 

 short time. The alcohol coagulates 

 the celloidin, and gives the mass the 

 consistence proper for cutting. Ab- 

 solute alcohol must be avoided, as it 

 dissolves out the celloidin. The ob- 

 ject can now be placed on a suitable- 

 sized cork, the surface of which is 

 covered with a few drops of the cel- 

 loidin solution or an ordinary (thick) 

 solution of gum arable, and the cork, 

 with object attached, is placed in or- 

 dinary alcohol to harden. After 

 hardening, the cork can be fastened 

 in the clamps of a microtome or held 

 in the hand, and the sections cut. 

 The sections can be stained, and 

 mounted in glycerin or in balsam. 

 When mounted in balsam, the sec- 

 tions must be cleared in oil of thyme 

 or bergamot, but not in oil of cloves, 

 as the latter dissolves the celloidin, 

 and renders the mounting of delicate 

 sections almost impossible. The cel- 

 loidin may be obtained of George In- 

 ness. F. W^. Murray. 



