422 SUMMARY OF CURRENT RESEARCHES RELATING TO 



b. Histolog-y. 



Intracellular Canals in Hepatic Cells.* — M. T. Browicz directs 

 attention to his own work, and to that of others, in demonstrating the 

 existence of intracellular canals traversing both cytoplasm and karyo- 

 plasm in the cells of the liver. 



Brown Fat in Rodents and Insectivores.f — M. Auerbach finds that 

 brown fat occurs in all the typical parts of the body in rats, mice, voles, 

 hares, hedgehogs, moles, &c. and in some of the typical regions in 

 scpiirrel, rabbit, and guinea-pig. None was found in badger or cat. It 

 appears that the occurrence of brown fat has no special relation to 

 hibernation ; it is absent from some hibernators, and it is present in 

 many forms which do not hibernate. It is not reduced to some fibrous 

 strands after hibernation, as Carlier reported, but may persist to a great 

 extent. In Myoxus muscardinus, Arctomys marmota, and Mus rattus 

 there is a distinct transition from brown to white fat. In hedgehog, 

 marmot, and Myoxus nitela it is not an absolute necessity that there 

 should be some feeding during the hibernating period. The sinking of 

 the body -temperature, the diminution of heart-beats and inspirations, 

 and the lowering of sensory acuteness, were verified in the marmot. 

 The primordium of a fat-organ was found in embryos of rat, mole, 

 rabbit, and cat. 



Evolution of Pyramidal Cells of the Cerebrum. \— P. Bamon y 

 Cajul has an important short paper — which should be translated — on 

 the phylogenetic changes in the pyramidal corpuscles of the cerebrum. 

 He notes that the idea of the supposed progressive evolution of these 

 elements, based on their diverse appearances throughout the Vertebrate 

 series, must be corrected by the fact that the plastic protoplasm relates 

 itself to the changing plan of cortical cerebral ^structure. But he has 

 much more to say, which we would summarise if we were more familiar 

 with his language. 



Cerebral Degenerations.§ — K. Kosaka describes, in reference to dog 

 and monkey, the secondary degenerations which ensue in the mid-brain, 

 pons, and medulla oblongata, after the destruction of the cerebrum, and 

 especially of the motor cortical centre. 



Arterio-Venous Anastomoses in Man and Mammals. ||— 0. Grosser 

 has made a detailed study of the anastomoses of arteries and veins at 

 the end of the extremities in bats, rabbit, rat, mouse, cat, and man. 

 The histological relations are noted, and the possible physiological 

 interpretations are discussed. 



Lympho-myeloid Connective Stroma in Testes of Young Rays.f — 

 A. Pollicard notes that the immature testis has in great part a lympho- 

 myeloid structure. This connective stroma is probably the seat of 

 Jeucocvte-formation, and it probably has a nutritive function in relation 



* Bull. Internat. Acad. Sci. Cracovie, 1902, pp. 130-6. 



+ Arch. Mikr. Anat., lx. (1902) pp. 291-338 (2 pis.). 



% Boll. Soc. Espan. Hist. Nat., ii. (1902) pp. 179-bO (2 figs.). 



§ MT. Med. Fac. Univ. Tokio, v. (1901) pp. 77-160 (4 pis.). 



|| Arch. Mikr. Anat., lx. (1902) pp. 191-216 (2 pis. and 2 bgs.). 



4 Comptes Rendus, cxxxiv. (1902) pp. 297-9. 



