330 General Notes. [ March, 
When the mass becomes nearly white and ceases to discolor 
the alcohol, it is ready for cutting. 
SEMPER’S METHOD OF MAKING DRIED PREPARATIONS.—Semper’s 
method, published in the Sitzungsber. d. phys.-med. Ges., Wirz- 
burg, 1880, and in the Zoolog. Jahresbericht for 1880, has been 
redescribed in detail by Dr. Sharp.! 
1. Place the object in a weak solution of chromic acid (4-1 
per cent), six to twenty-four hours, according to its size and 
nature. For small animals, such as annelids, gastropods, frogs, 
mice, &c., six to eight hours are sufficient. 
2. Transfer to a large quantity of clean water, which must be 
often renewed until the acid has been so far withdrawn that the 
water remains uncolored by it. This part of the process may be 
much shortened by allowing a current of water to flow through 
the vessel. The usual time is from ten to twenty hours. 
3. Treat with thirty to forty per cent alcohol ten to twenty-four 
hours, with sixty to seventy per cent alcohol two or three days 
(with larger objects a week), with ninety per cent alcohol two or 
three days or more, and finally with absolute alcohol.? 
4. Transfer to turpentine and leave it until it becomes thor- 
oughly saturated (two to three days). With large objects it is 
best to change the turpentine once. 
5. Place the preparation in the air, in order to evaporate the 
turpentine, protecting it carefully from dust. 
e preparation soon becomes white, resembling the whitest 
kid. It is light, stiff and, on account of the resin contained, per- 
fectly insect-proof. 
If hollow organs (stomach, bladders, lungs, &c.) are prepared, 
they may be inflated with air after they have remained a short 
time in turpentine, by so doing much space, and consequently 
much alcohol, are saved 
Professor Semper keeps his preparations in dust-proof, glass 
boxes, in which they can be seen from both sides. 
To the five steps of the process a sixth, discovered by Semper 
a few years ago, is given by Dr. Sharp. It consists in placing 
the prepared object in a solution of glycerine and sugar, which 
brings back almost entirely the original color in many cases. 
Rast’s METHODS oF Srupyinc KARYOKINETIC FIGURES — 
Material—The skin and kidney of Proteus and the epithelium 
of the mouth of salamander larva. The epithelium is the more 
favorable object, as the very large nuclei can be examined in sur- 
: hag Acad. Nat. Sci. Philad., 1884, pp. 24-27. 
oN RS radio etary Sigg the most critical part of the whole process- 
Absolutely every particle of the water must be removed; for any tissue in which it 
a: Femratas will become ed and eventually spoil. Dr. Sharp always takes the pre- 
~ Caution of changing absolute alcohol once or twice, and leaves the object in it 
SS 
a3 ok Morph. Jahrb., X, H. 2, pp. 215-219, 1884. 
