392 The Study of Zodlogy in Germany. [July, 
pression strains which take place in the synclinal fold of the 
Cumberland. It is readily to be perceived that the nature of the 
strains developed by the synclinal folds must vary greatly from 
those which are formed beneath the anticlinals of a mountain 
district. 
I only propose to call attention to the great problems in struct- 
ural geology which this region presents to us, with a view of in- 
teresting our students of dynamic geology in their solution. 
More extended discussions of these questions will be given in the 
forthcoming volumes of the Memoirs of the Kentucky Geological 
Survey. r 
THE STUDY OF ZOOLOGY IN GERMANY. 
BY CHARLES SEDGWICK MINOT. 
Il THE METHODS USED IN HISTOLOGY AND EMBRYOLOGY. 
THE use of the microscope goes hand in hand with the work of 
zoölogists in Germany, and it is there that we find the great- 
est number of means employed to render the objects suitable for 
examination. I have frequently heard American zoölogists ex- 
press a slight distrust of histological methods, — well founded, 
perhaps ; it ought not to lead to the rejection of the benefits to 
be obtained from using them, but merely to greater caution in 
employing them. 5 
It is well known that animal tissues and organs consist of cells 
of various kinds, variously grouped together. The forms which 
these cells can assume lead to the most curious transformations, 
so that things as different from one another as muscular fibres, 
blood corpuscles, and ganglion cells can be traced as modifica- 
tions of the same primitive form. The work of microscopic an- 
atomists is to detect the changes which the simple cells of 
embryos undergo in the course of their transformations into the 
components of the tissues of the adult, and to investigate in de- 
tail the final results of these metamorphoses. It is much to be 
- desired that America should assist more in this work, and it i 
.with the hope of stimulating some persons to do so that this 
„article is written. 
In the tissues of the adult we find the cells arranged in a def- 
inite manner, and we have consequently to examine the shape 
and character of the single cells, and then their relation to one 
another. Simply placing a small piece of an organ underneath 
