524 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Comparative Study of Hair.* — Dr. W. G. Reynolds has a paper on 
this subject which hardly admits of summary. We note it on account 
of its practical interest to the medico-legal expert, or to the microscopists 
whom he may consult. 
Organs of Taste.f — Dr. A. E. Loveland has studied these both in 
the human foetus and in the adult. His results are mainly confirmatory. 
Gustatory or sensory cells and sustentacular or supporting cells are 
distinguished. The central prolongations of the gustatory cells end 
bluntly in the tissue, and nerve-fibrils come everywhere into close 
apposition with them, though there is no actual communication. The 
nerve-fibrils ramify and form various networks, both around and within 
the taste-bulbs, but the further distinction between perigemmal and 
intergemmal external fibrils is superfluous. The sub-epithelial cells 
may be auxiliary to the taste function, and may be regarded as “ secondary 
sensory ” cells, as Retzius called them. 
Muscle-Fat in the Salmon.J — Mr. S. C. Mahalanobis finds that the 
fats taken with its food by the salmon in the sea accumulate between 
the muscle-fibres and also inside the fibres between the fibrils, and that 
during the sojourn of the fish in the river these fats steadily diminish, 
being either used up as a source of energy by the muscle, or trans- 
ported from the muscle to the growing ovaries. There is no evidence 
of fatty degeneration ; and many cases of so-called fatty degeneration in 
other animals are merely such interfibrillar infiltration as occurs in 
the salmon’s muscle. § 
c. General. 
Origin of Vertebrata.|| — Prof. E. Perrier states eight essential 
characteristics of Yertebrata: — (1) bilateral symmetry and metamerism ; 
(2) the presence of cilia ; (3) gill-clefts ; (4) a closed vascular system 
and a ventral heart; (5) nephridia; (6) notochord; (7) dorsal nerve- 
cord ; (8) an inverted position compared with lower animals. Applying 
the method of exclusion, he rejects theory after theory until only the 
Annelid theory is left. This is not done, however, without making 
many assertions which are subjects of legitimate difference of opinion. 
Origin of Mammals.^ — Prof. H. F. Osborn marshals the evidence in 
favour of the general conclusion that the Theriodontia constitute a 
group which contains practically all the primitive characters of the 
Mammalia in the skeleton and teeth, and that no other reptiles or 
amphibians approach so near the hypothetical pro-mammal. The ex- 
planation of amphibian characters in the soft parts of existing mammals 
may be that the pro-mammal sprang from primitive reptiles which 
preserved a number of still more primitive amphibian or stegocephalian 
characters. 
Theory of Limbs.** — Dr. H. Braus has made a detailed study of the 
innervation of the limbs in Selachii, Holocephali, and Dipnoi, and bases 
* Trans. Amer. Micr. Soc., xix. (1897) pp. 117-28 (2 pis.). 
f Tom. cit., pp. 129-74 (3 pis.). 
X Government Report of the Fishery Board for Scotland, 1898, pp. 10G-11 
(4 pis.). § Cf. infra , p. 525. 
II Comptes Rendus, cxxvi. (1898) pp. 1479- 8ti. 
U Amer. Nat., xxxii. (1898) pp. 309-34 (14 figs.). 
** Jenaische Zeitschr. f. Naturwiss., xxxi. (1898) pp. 230 4GS (S pis. and 3 figs.)- 
