526 General Notes. [ May, 
MICROSCOPY. 
SOME ANATOMICAL AND HISTOLOGICAL Metuops.2—J/, A modi- 
fication of Semper s method of making dry preparations —While it 
may be true that in many cases the preparations made according 
to Semper’s method have an appearance similar to a gypsum 
model, they quite often present a dingy, weatherbeaten aspect 
that is by no means agreeable. The thin membranes and the 
connective tissues of dissections are left in a loose, wooly condi- 
tion that grows worse by handling. 
The microscopist completes his work by mounting his prepa- 
rations in a solution of balsam. In like manner Semper’s metho 
may be completed by saturating the preparation with some solid 
that would fill up the pores, bind the parts together and restore 
the natural appearance. The solid which I have employed for 
_this purpose is a mixture of Canada balsam, paraffine, and vasel- 
ine, but it is probable that a soft paraffine will in most cases do 
quite well. It is necessary that the mixture shall melt at about 
46° C. (115° F.). It will be seen that the preparation is treated 
just as the microscopist treats an object when he wishes to obtain 
a consecutive series of sections. While yet saturated with the tur- 
pentine, it is to be immersed in the mixture, heated a little above 
the melting point and kept there until all the turpentine has been 
replaced. In many, if not in most cases, however, the turpentine 
may be allowed to evaporate before the preparation is put into the 
melted paraffine mass. The latter then quickly penetrates the 
tissues and the work is simplified. The preparation is then to be 
kept in an oven vessel warm enough for the excess of paraffine to 
melt and drain off. It may then be wrapped in cloths or in 
bibulous paper until the whole of the paraffine mixture adhering 
to the outside has been dried off. 
The advantages to be derived from pushing the process to this 
stage are the attainment of a greater degree of firmness and 
strength in the specimen, the obviation of the bleached appear- 
ance assumed on the escape of the turpentine, and the restoration 
of the natural colors. Probably any colors will reappear that will 
endure immersion in alcohol. In the case of anatomical prepa- 
rations made in the way described, injected vessels show to ad- 
vantage. I have also prepared specimens of lizards, small turtles, 
‘fishes, mussels and earthworms; and whenever the tissues have 
been thoroughly saturated with the wax mass, the results have 
been satisfactory. 
_ LL, A method of making double injections for dissecting pur- 
poses.—A brief notice of Professor H. F. Osborn’s method for 
-double injections appeared in Science Record, 11, Feb. 15, 1884, p. 
4. His plan appears to have been to fill the whole vascular 
SD Po by ce y Bart pera Comparative Zoology, Cambridge, Mass. 
