and Laboratory Methods. 1539 



Born-Peter ridges. 7. There is no necessity for filling up the scratches, or for 

 coating the ridges with amorphous color, nor for the addition of color, lacquer, 

 or any foreign substance. 8. Each section bears its directing marks in the shape 

 of circumscribed black spots. 9. The detecting strands cause no inconvenience 

 at any time in the processes, and their axes are for all practical purposes as 

 accurately perpendicular to the plane of section as are the colored ridges of the 

 Born-Peter block. 10. It is possible, but not yet fully tested, to apply the pro- 

 cess to celloidin. a. m. c. 



Stepanow, E. M. Eine neue Einbettungsmeth- The author uses a solution of celloidin 

 od in Celloidin. Zeit. f. wiss. Mikros. u. . , .... , 111 



f. Mikros. Techn. 17: 185-191, 1900. 1" clo^e Oil with ether and absolute 



alcohol in the following proportions : 

 Celloidin (shavings very fine and well dried), 1.5 gr.; clove oil, 5.0 c. c; ether, 

 20.0 (of 0.720 sp. gr.) ; alcohol absolute, added by drops, 1.0 c.c. One c. c. of this 

 mixture contains more than 6 per cent, celloidin, corresponding to the weakest 

 used solution. By the addition of ether and alcohol much thinner liquid can be 

 obtained, and by concentration thicker up to 35 per cent. The process with the 

 " normal " solution (6 per cent.) is as follows : Tissue well hardened in alcohol, 

 dehydrated, and freed from superfluous alcohol by touching it lightly with filter 

 paper, is put in a glass-stoppered bottle containing 4-5 c. c. of clove-oil-ether- 

 celloidin. According to the size of the pieces, it is kept here from one to six 

 hours or more, then the bottle is uncorked and put under an inverted glass, 

 leaving the solution to evaporate for four to six or more hours. This thickened 

 mixture is poured into a small, freely hanging filter of fine silk paper ; the mass 

 is then either left open or loosely closed to reduce it to embedding consistency. 

 The process may be hastened by keeping the filter in a warm place. The clear- 

 ness and dryness of the substances are the best assurances for a good embedding 

 matrix. This thickening takes place in from four to six hours ; the object is 

 then cut out from the surrounding mass. Further preparations may follow one 

 of several lines : 1. If the sections are to be cut in alcohol the material is 

 mounted on a cork which has been well coated with celloidin and then put 

 for twenty-four hours in 70-85 per cent, alcohol. Treatment for two to three 

 hours in chloroform, is equally sure and much quicker. 2. The object, fastened 

 on a piece of wood, is made firm, by means of a needle, to the cork of a bottle 

 containing chloroform, for two to six hours, then the sections are cut with a dry 

 knife and transferred with oil to a slide. Sections 10, 7.5, and 5 /< can be cut 

 this way, and the block is always transparent. 3. The best method is to put the 

 freshly embedded object into benzol, and there it hardens. Such an object may 

 be put directly into anethol (later into anethol-paraffin) ; into a solution of 

 paraffin in benzol, and then into liquid paraffin ; into cedar oil for dry sections, 

 or into 85 per cent, alcohol for wet sections. 



The chief advantages of the method are: 1. The manipulations are as sim- 

 ple as in the ordinary methods, and fewer. 2. The imbibition is more quickly 

 completed (twenty-four hours or fewer). 3. The embedding is so thorough that 

 sections can be cut 3 // in thickness. 4. The control of the embedding processes 

 is easily indicated by transparency. 5. After these preliminaries the tissues may 



