ZOOLOGY AND BOTANY, MICEOSCOPY, ETC, 255 



regenerate. The presence of taste bnds in a barbel is dependent on the 

 presence of a normal nerve in the barbel, since the taste bnds degenerate 

 and disappear when the nerve degenerates, and reappear when the nerve 

 has regenerated. Likewise, the power of a barbel as a whole to re- 

 generate a missing tip is dependent npon the presence of a normal nerve 

 in that barbel. The theory that certain chemical substances of the 

 nature of hormones are given out by the nerves, and that such substances 

 are necessary to the existence of taste buds and also for the regeneration 

 of the barbel as a whole, accounts for all the phenomena of degeneration 

 and regeneration in the barbel of Amiurus. J. A. T. 



Development of Blood-vessels in Amphibia. — Tanzo Yoshinaga 

 {Acta Scholse Med. Univ. Imper. Kioto, 1920, 3, 401-39, 6 pis., 5 figs.). 

 The endocardium and endothelium and their caudal prolongation 

 (vitello-intestinal veins) are laid down as discrete mesodermic cells of 

 splanchno-pleural origin. The endoderm does not share in forming the 

 heart or vessels. The free cells that form the primordium of the heart 

 and vessels separate simply in loco from the splanchno-pleure, which is 

 thereby thinned. The free cells do not wander from their place of 

 origin. At an early stage the vascular system is- thus represented by 

 strands of cells. But these do not form indifferent cell-masses, but 

 definitive vascular strands which form the endothelium. The separated- 

 off cells which originate the primordia of heart and vessels should not 

 be called mesenchyme ; they arise as an histological differentiation of the 

 mesoderm. J. A. T. 



Myotomic Contractions in Dogfish Embryos. — P. Wintrebeet 

 (Comptes Rendus Soc. Biol., 1920, 83, 1-467-70). In aneural embryos of 

 Scylliorhinus canicula each of the lateral muscular bands acts indepen- 

 dently of the other and of other organs. The amplitude of the movement 

 remains the same for a definite period of growth, but changes of tem- 

 perature have a marked effect. In a uniform medium warmth accelerates 

 the rapidity of the movements and has still more effect in lessening the 

 duration of the pause. In a variable medium abrupt changes of 

 temperature disorganize the movements. Yan't Hoff's law does not 

 seem to apply, not in any case for minute changes of temperature. It 

 is probable that each animal has a specific irritability in relation to 

 warmth, and even different muscles of one and the same animal vary in 

 their reaction. J. A. T. 



Exaggeration of Islands of Langerhans in Offspring of G-lyco- 

 suric Mother. — G. Dubeeuil and — • Andeeodias {Comptes Rpiidus Soc 

 Biol., 1920, 83, 1490-3, 2 figs.). In a new-born offspring, of abnormally 

 large size, surviving only a few minutes, the islands of Langerhans in 

 the pancreas were twenty to thirty times larger than the normal. This 

 hypertrophy is interpreted as a response to the excessive quantity of 

 sugar in the blood passing from the glycosuric mother through the 

 placenta into the offspring, and causing foetal hyperglycemia. J. A. T. 



Nerve and Plasmodesma. — H. Y. Neal (Journ. Comp. Neurology, 

 1921, 33, 65-75, 5 figs.). One of the disputed points in the histo- 



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