SUMMARY OF CURRENT RESEARCHES RELATING TO 
99 
after birth, or whether they simply hypertrophy. In the field mouse, 
the cat, and the tame rat, hypertrophy of the fibres occurs, accompanied 
by a reduction in their number, “ hypertrophy accompanied by aplasia.” 
There is in fact a struggle and a survival of the fittest. The paper is 
an interesting concrete illustration of the idea of intra-organismal 
struggle with which Roux and others have made us familiar. 
Cuticular Structure.* — Herr A. Wolff finds fine parallel striation 
in the cuticle of the epithelium of the snail’s horns and of the tail of 
larval salamanders. In such places it is impossible to think of digestive 
or absorptive (?) function, as is suggested in connection with the cuti- 
cular striation of intestinal epithelium. This makes it doubtful whether, 
in the last-named case, it has anything to do with the passage of 
emulsified fat. 
Origin of Epithelial Tissue.! — MM. A. Sabatier and E. de Rouville 
maintain that the epithelium finds a very active auxiliary in the sub- 
jacent connective tissue. A connective tissue cell may become epithelial ; 
in fact the connective tissue acts like a post-embryonic blastoderm, and 
may give origin to endodermic as well as ectodermic epithelium. Ami- 
tosis is a simple and rapid mode of division exhibited by elements which 
have a maximum of vitality. 
Direct Division.^ — Hr. W. Karpow has studied this in the tracheal 
epithelium of the cockchafer, in the chorion of mammals, and in the 
epidermis of the frog, and regards it as due, in part, to the vegetative 
growth of the nucleus, and, in part, to mechanical conditions of pressure. 
Inter-Renal Body of Selachians.§ — Dr. A. Kohn has studied this 
body iu Selachians and in its relation with similar structures in other 
Vertebrates. It is an unpaired body, situated dorsally between the 
caudal portions of the kidneys. Its nature is epithelial, and it consists 
of ramified cellular strands, between which there are thin-walled blood- 
vessels. Fat globules in the epithelial cells give the organ its yellow 
colour. The supra-renal bodies are quite different, representing portions 
of the sympathetic ganglia, and containing, besides a few of the typical 
elements of these, a predominance of “ chromaffine cells.” But though 
the inter-renals ( Nebenniere ) of Vertebrates are essentially epithelial, 
they contain, from Amphibians onwards, an increasing amount of sym- 
pathetic tissue with all its elements. They have no typical glandular 
character nor ejnthelial ducts, and may be compared to the epithelial 
bodies in the vicinity of the thyroid. 
Path of the Spermatozoa from the Testis of Frogs.|| — Dr. H. 
Beissner has reinvestigated this subject, in regard to which previous 
observations are very discrepant. In Rana fusca the spermatozoa pass 
from the testis through the vasa efferentia, which traverse the mesor- 
chium, and unite on the median margin of the kidney with Bidder’s 
longitudinal canal, whence they pass onwards through the ampullae and 
transverse canals into the ureter. But in R. esculenta the path is 
* Anat. Anzeig., xv. (1898) pp. 148-51. 
t Comptes Rendus, exxvil. (1898) pp. 704-6. 
X Ann. Inst. Econ. Rurale Moscou, v. (1897). See Physiol. Russo, i. (1898) p. 112. 
§ Arch. Mikr. Anat., liii. (1898) pp. 281-312 (1 pi.). 
|| Tom. cit., pp. 168-79 (1 pi. and 2 figs.). 
