ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 41 



Comparative Histology of Cartilaginous Cells.* — Joannes Chatin 

 has a brief note on the extraordinary polymorphism of cartilage cells, 

 which are usually described as ovoid or spheroidal except in rare cases. 

 The fact is that it is a very variable element, occurring in spheroidal, 

 "cylindrical, claviform, ovoid, angular, multiloba te, branched, stellate, and 

 •other shapes, all connected by intermediate phases. 



c. 



General. 



Phototropism in Animals.f — Em. Radl has made many experiments, 

 especially with Arthropods, on the wide-spread phenomenon of photo- 

 tropism. Many animals, from Ccelentera to Molluscs, orientate their 

 body in relation to the direction of light; many move actively to or 

 from the light, orientating themselves meanwhile. It is a primitive 

 reflex, and though it is not definitely proved, the author says, in 

 Protozoa, it occurs familiarly in unicellular plants. Many interesting 

 subjects are discussed — the behaviour of animals on a rotating turn- 

 table, the compensatory head-movements of insects, nystagmus in insects, 

 and the flight of moths and the like into the flame. The phototropic 

 phenomena are considered in relation to other tropisms, and in connec- 

 tion with the general problem of orientation. Kadi's general position is 

 that, under the influence of external and internal forces, working, so to 

 speak, in opposed couples, the organism comes to assume a position of 

 static and also physiological equilibrium in reference to the direction of 

 the light. 



Coloration in Mammals and Birds.J — J- L. Bonhote seeks to show 

 that the colour of a bird or mammal is primarily due to " activity of 

 nutrition and function." This he terms " vigour," which is dependent 

 on (a) climate, containing two factors, temperature and food, and (b) the 

 rise and fall of sexual activity. AVhere conditions for high vigour exist, 

 the majority of the animals will be brightly coloured. Tlie individual 

 vigour of various species and groups will differ, and one animal may be 

 able to maintain a full vigour under conditions which would be im- 

 possible to another. This will account for some of the Polar animals 

 becoming strongly coloured, e.g. musk ox, raven, penguin. Shortly 

 before the moult in many animals the colour of the pelage fades, 

 beginning along certain definite areas and from certain centres, termed 

 " pcecilomeres ;" this bleaching is physiological, and the patches so pro- 

 duced thus owe their inception to internal rather than external causes. 



Relation of Oxidation to Functional Activity.§ — Sir John Burdon- 

 S.niderson opened a discussion on this subject at the British Association 

 Meeting at Cambridge. He particularly contrasted the chemical pro- 

 cesses of gland function and muscle function. Whereas the former is 

 not in any marked degree katabolic, the dominant process in the oxida- 

 tion which is inseparably associated with the performance of muscular 

 •function is katabolic. Oxygen seems to play two parts in metabolic 



* Comptes Rendus, cxxxix. (1904) pp. 489-91. 



t UntersuclmngenuberdenPhototropisimisderTiere. 8vo. Leipzig (1 903) 1S8 pp. 



! Journ. Linn. Soc. (Zool.) xxix. (1904) pp. 185-7. 



$ Nature, lxx. (1904) pp. 590-3. 



