314 SUMMAKY OF CUKKENT RESEARCHES RELATING TO 



divides into two uninucleate daughter-individuals, which become 

 binucleate. Cysts are unknown. The food consists of small vegetable 

 organisms in the intestinal contents. J. A. T. 



Intracellular Respiration in Paramecium. — E. J. Lund (Amer^ 

 Journ. Physiol., 1918, 45, 351-73) has studied in Paramecium candatum 

 the relation of oxygen concentration and the rate of intracellular oxida- 

 tion. He finds that the oxidations stop when the cell is killed by too 

 high oxygen-concentration, but below the limit of fifty-five times the 

 minimal concentration the rate of intracellular oxidation is independent 

 of the concentration. The rate is entirely independent of the toxic 

 action of potassium cyanide, but intracellular oxidations stop when the 

 animal undergoes cytolysis in cyanide solutions. J. A. T. 



Experimental Induction of Endomixis in Paramecium aurelia. — 

 R. T. Young {Journ. Exper. ZooL, 1017, 24, 35-53, 3 pis. referred to^ 

 not in number) finds that endomixis can be induced experimentally, 

 especially by the use of metabolic end-products (e.g. waste products of 

 Infusorians), and by increasing the rate of metabolism of the animals 

 themselves. It is not a lethal process, but may be associated with a 

 temporary depression. It is more or less cyclical in character, and 

 probably has a rejuvenating function. It is not, however, a necessary 

 accompaniment of temporary depressions, and may not be followed by 

 rejuvenation. Other factors are concerned in determining the division- 

 rate. Its rate to parthenogenesis in Metazoa is not clear. J. A. T. 



Reversibility of Morphogenetic Processes in Bursaria. — E. J. 

 Lund {Journ. Exper. ZooL, 1917, 24, 1-33, 38 figs.) finds that 

 de-differentiation of the gullet of this Ciliate always occurs before 

 division, encystment, and regeneration of lost parts of the cell, and also 

 spontaneously. But the primordium of the gullet remains, and from 

 it a new gullet is formed by differentiation. The processes are re- 

 versible. They concern changes in relatively unstable, secondary struc- 

 tures in the cell, and do not visibly affect the more stable nuclear 

 mechanism. The author finds evidence for the existence of a specific 

 type of physical-chemical mechanism for de-differentiation similar in its 

 action to the mechanism of autolysis. J. A. T. 



Trypanosomes in Monkeys.^M. Leger and E. Parry {C.R. Soc, 

 Biol. Paris, 1918, 81, 180-3) report the occurrence of some new non- 

 pathogenic Trypanosomes in South American monkeys — a very distinct 

 form {Trypanosoina lesourdi sp. n.) in Ateles pentadadylus; and another 

 {T. devei sp. n.) in Midas midas, with the general features of non- 

 pathogenic forms from small mammals. J. A. T. 



New Microsporidian in Cabbage White Caterpillars. — A. Paillot 

 {C. R. Soc. Biol., 1918,81, 187-9,26 figs.) describes Perezia leyerisTp.n., 

 from caterpillars of Pieris brassicse, especially in adipose tissue and 

 certain giant cells of the blood. An account is given of the schizogony, 

 the sporogony, the maturation of the spores, and the emergence of a 

 binucleate unit from the spore. The new species is near P. mesniliy 

 previously described. J. A. T. 



