ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 31 



lobular. Lvinphocytes occur in the blood and connective-tissue before 

 they are in the thymus. They migrate into the epithelial primordium 

 of the thymus. 



Larvae of Apodous Fishes.*— Louis Roule distinguishes the Tilurus- 

 type, with a ribbon-like body and a caudal filament, from the Lepto- 

 cephali(s-tj])e, with a more oblong body and no caudal filament. It 

 may be that Tihirella is one of the larval phases of a Nemichthyid, but 

 it is difficult to suggest the syetematic position of TiUirus and Tiluropsis, 

 except that they present certain affinities to the Muraenidie or to the 

 Simenchelydte. 



''• Histology. 



Fatty Substances in the Thymus. f — Ruben Holrastrom finds in 

 the rabbit's thymus a normal occurrence of fine granules and globules 

 of fat and fat-like substances. These occur in the cortex. They increase 

 as life goes on ; they have nothing to do with the interstitial formation 

 of fatty tissue ; they represent a normal involution process. In the 

 rabbit they occur chiefly in the cortex ; in the cat, in the medulla. 



Artificial Rejuvenescence of Tissues in Culture. J — Alexis Carrel 

 points out that the life of tissues in culture is very limited. After 3-15 

 days' growth becomes slow and stops. The tissue then dies. But this is 

 not necessary. Death may be due to the accumulation of the products 

 of katabolism. If the tissue is lifted on a cataract-knife and bathed in 

 Ringer's solution, either of normal strength or slightly hypotonic ; and 

 if it is thereafter placed in a hypotonic medium of three parts plasma 

 and two parts distilled water, then the senescence is staved off. The 

 rejuvenescence treatment may have to be repeated several times. After 

 its ninth treatment a culture of connective-tissue grew with great activity 

 ou the thirty-fourth day after its excision from the organism. Within 

 limits, senescence and death are contingent not necessary phenomena. 



Changes in the Nucleus-cytoplasm Relation in Parasitized Cells.§ 

 M. Siedlecki finds that in cells parasitized with Gregarines and with 

 Carydtrffpha mesnili there is a close inter-relation between the metabolism 

 of the cell and that of the parasite. There is a demonstrable relative 

 increase in the nuclear substance of the host-cell, as happens in cases of 

 energetic function, starving, and degeneration. There is no evidence of 

 degeneration ; there is little evidence of starving ; it seems that the 

 parasite and the host together have a more intense metabolism than an 

 intact cell. 



Sinus Hairs of Ox.|l— D. Tretjakoff describes in great detail the 

 diverse nerve-endings in connexion with the sinus hairs about the snout 

 and lips and other parts of the ox. It seems that the sinus hairs reacii 

 their climax here, and play an important part in the recognition of 

 different kinds of plants. The complex innervation is remarkable. 



* Comptes Rendus, cliii. (1911) pp. 732-5. 



t Arch.Mikr. Anat., Ixxvii. (1911) pp. 323-45 (1 pi.). 



t C.R. See. Biol., Ixxi. (1911) pp. 401-2. 



§ Bull. Internat. Acad. Sci. (1911) pp. 513-23 (1 pi.). 



II Zeitschr. wiss. Zool., xcvii. (1911) pp. 311-116 (1 pis.). 



