ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 241 



impulses may be inhibited by the results of experience. In schools of 

 sticklebacks swimminor t02;ether there is no evidence of intelligent 



^a ""& 



purpose, other than that many may follow the dart-movement made by 

 one. J- A. T. 



Colour-sense in Diurnal Birds. — Erna Raks (Zeitschr. tviss. Zool., 

 1916, 116, 1-42, 1 pi., 7 figs.). Experiments with blue exotic birds, 

 such as parrots, yielded few satisfactory data. In some, e.g. Ara, sight 

 is not the only guide in seizing food. Others, e.g. Mdopsittacus and 

 Cijanospiza, seemed unable to become accustomed to take their food on 

 an area illumined by light of different colours. On the other hand, 

 fowls seem readily able to see blue colours. They picked up blue seeds 

 and uncoloured seeds in a blue area ; they made no use of those in 

 ultra-blue or ultra-violet areas. Hess found that his fowls did not use 

 blue seeds, but Hahn points out that this was probably because they had 

 no association with blue food. Hess thought that his birds did not see 

 blue objects because of coloured drops of oil in the cones of the retina. 

 Hahn finds that these oil-drops vary greatly in different kinds of fowls. 



J. A. T. 



Reactions of Dogfishes to Injections. — E. R. Hoskins and M. M. 

 HosKiNS (Jouni. Expe.r. Zool., 1918, 27, 101-155, 6 pis.). Various 

 non-toxin solutions and suspensions (including vital dyes) were injected, 

 and also various excretory toxins. The digitiform gland of Mastelus 

 excretes about a cubic centimetre a day of clear alkaline fluid contain- 

 ing urea. Certain injected solutions, but no suspensions, were recovered 

 in this excretion. Injections of excretory toxins injure this gland. The 

 Selachian kidney is a less efficient excretory organ than the mammalian 

 kidney. The liver is relatively a very efficient excretory organ. The 

 spleen is very well adapted for phagocytic activity, and is stained deeply 

 by injected insoluble dyes. Injected particles produce leucocytosis. Toxins 

 cause congestion in the spleen, the endothelium appears to be injured, 

 peculiarly shaped nuclei may be produced, and many nuclei become 

 hyperchromatic. The spiral valve has some excretory function, the 

 stomach none. Excretory toxins pass through the epithelium of the 

 spiral valve and destroy it, although they do not injure the intestine 

 immediately anterior to or posterior to the spiral valve. The endo- 

 thelium lining the arterial arches, and especially the large sinuses in the 

 gills, is very phagocytic to injected trypan-blue and coarsely powdered 

 carmine. It stores such substances in concentration greater than that 

 in any other cells examined, and at the same time it proliferates and 

 produces free phagocytes which circulate through the body. J. A. T, 



Blood and Blood Gases in Hibernating Woodchuck.— Andrew T. 

 Easmussen {Amer. Jourii. Physiol., 1916, 39, 20-30; ibid., 41, 162-172, 

 ibid., 464-82). During hibernation in Marmota monax the blood has 

 an extra amount of CO., ; there is reduced alkalinity and this diminishes 

 the power the blood "'has of absorbing CO.^ ; the difference between 

 venous and arterial blood as regards gases is much accentuated. The 

 amount of CO^ increases during hibernation and decreases on awakening. 

 The percentage of oxygen in the arterial blood is greatest "mmediately 



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