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1877.] The Study of Zoölogy in Germany. 397 
without alteration, and Ranvier’s picrocarmine has certain advan- 
tages; but on the whole, I have found the above-mentioned mix- 
ture of acetic acid and ammoniacal carmine to be quite sufficient 
for most work. 
Hzmatoxiline, on the other hand, has to be employed in a 
particular solution. Dissolve first thirty-five parts of hamatoxi- 
line crystals in one thousand parts of absolute alcohol, and mix it 
cold with a solution of ten parts alum in three thousand parts 
distilled water. The mixture is purple at first but turns a deep 
blue in the course of a few weeks; but it may be used without 
waiting for the change of color. For use it must always be fil- 
tered through porous paper to free it from sediment, and it may 
be advantageously diluted with 0.5 per cent. solution of alum. 
It acts much more quickly and produces a deeper and more exclu- 
sive staining of the nuclei than does carmine. It is therefore par- 
ticularly applicable in those cases where it is desired to study the 
shape and transformations of nuclei, as, for example, in tracing 
the development of spermatozoa. A figure is here added to 
show how beautifully the changes can be followed in sections of 
the testicle of Epicrium glutinosum, one of the Cceciliade or 
footless, worm-like amphibians. The testicle is divided up into 
numerous follicles, and the cells in each are all in one stage, while 
the various follicles present various degrees of development ; 
thus in a single section all the principal alterations may be ob- 
served. The. cells (Figure 71) are he b | % 
round at first with a very large Oz a 
granular nucleus (a). They then @ 
divide, becoming smaller‘and more j 
numerous (b). The next change f 7 ` 
is a slightly irregular elongation of È HY 
cell and its nucleus, slight at first (F10. TL) DEVELOPMENT OF THE SPER- 
(e), but gradually increasing (d). MATOZOA OF EPICRIUM GLUTINOSUM. 
At this point in the metamorphosis the protoplasm is gathered 
at one end of the cell, and the long nucleus at the other, and it 
at once becomes evident that the nucleus is to make the head of 
the spermatozotn, the protoplasm the tail. At this stage the 
cells lay themselves in rows (e), the nuclear ends, or as we may — 
now call them the heads of the young spermatozoa, all point- 
ing the same way. Each cell continues to elongate until it 
grows into a fully developed spermatozoon ( J), with a pointed 
front end, a long head which appears almost black when stained | 
With hematoxiline, and a long, fine tail. The development of the 
