984 The American Naturalıst. [October, 
been found. The fires could not have been those of charcoal pits, nor 
was it a lime-kiln. There must have been an immense amount of fuel 
collected to burn this mass of clay and stone.’’ ‘The theory of crema- 
tion was discussed, but if these are crematories it is quite remarkable 
that no bones or remnants are found. 
MICROSCOPY. 
Demonstration of the Chromosomes.?—In the preparation 
of the egg for tracing the history of the nuclear elements, Boveri em- 
ployed two methods. In one, the preservative fluid was a mixture of 
picric and acetic acid, and the staining fluid borax-carmine; in the 
other, which was the principal reliance, Schneider's acid-carmine 
served both as a preservative and staining medium. The living egg is 
followed under the microscope until the desired stage is reached ; then 
a drop of acid-carmine is added at one side of the cover-glass, and 
drawn under by the aid of a bit of filter-paper applied at the opposite 
side. After 5-30 minutes the fluid is replaced by glacial acetic acid, 
which decolorizes all parts of the egg except the chromosomes, and at 
the same time renders the cytoplasm quite clear, while giving a sharp 
definition to the chromatic elements. The achromatic elements are 
not well preserved. 
The egg so prepared is mounted in glycerine. In order to determine 
the exact number of chromosomes it was often found necessary to 
press the egg more or less, and thus separate the chromosomes a little. 
These preparations last for only a few days. 
Caryokinetic Figures.*— Dr. Solger calls attention to the fact 
‚ that the amnion of the rat is more convenient material for exhibiting 
the caryokinetic figures than the mesentery of the young rabbit (rec- 
ommended by Orth in his ** Cursus der Normalen Histologie’). The 
advantage of such material is that it can be prepared without the neces- 
sity of imbedding and cutting. 
The freshly-excised uterus horn is placed in a saturated aqueous so- 
lution of picrid acid, and then the egg-membranes—at least the chorion 
—is cut open with scissors. The amnion (of embryos 1.8 cm. long to 
2 cm.long) then floats as a very thin membrane, or asa closed sac 
still envelops the embryo. 
! Edited by C. O. Whitman, Clark University, igo Mass. 
? Boveri. Jen. Zeitschr. XXIV., 2 and 3, 1890, p. 
3B. Solger. Arch. f. mik. Anat., XXXIIL., 4, p. sie „1889. 
