1768 Journal of Applied Microscopy 



be tested. One set of dishes was then exposed to strong sunlight from which 

 the heat rays had been absorbed, while the other set was kept in the dark, the 

 temperature conditions being the same in both cases. The poisonous action of 

 these substances (indicated by the length of time the cilia continued to beat) 

 was found to be very markedly increased by the action of the light. The speci- 

 mens kept in the dark lived in some cases five and six times as long as those ex- 

 posed to the light. The action of a fluorescent, non-toxic substance asculinwas 

 not different when in light from what it was in the dark, and the same was found 

 to be true of a toxic but non-fiuore§cent substance (acid fuchsin) under similar 

 conditions. The conclusion is reached that light increases the toxic action of a 

 fluorescent substance on ciliated epithelium. r. p. 



Greeley, A. W. On the Analogy between the In the first of these two studies on the 



Effects of Loss of Water and Lowering of physiological effects of low tempera- 



lemperature. Amer. Jour. Physiol. 6:122- . . 



128, 1901. ture it is shown that the common blue 



Artificial Parthenogenesis pro- Stentor {StetUor cariileus) goes into a 



duced by a Lowering of the Temperature. . ,. . , • i 1 



Ibid, 6: 296-304, 1902. restmg condition characterized by 



absorption of the cilia, disappearance 

 of the gullet and throwing off of the ectosarc, when the temperature is gradually 

 lowered to about 0° C. By gradually raising the temperature the organism may 

 be brought back to its normal condition. Raising the temperature above the 

 normal (up to 25°-28° C.) strongly stimulates cell divison. If the organisms are 

 put into an -f^ solution of cane sugar, which of course causes a loss of water 

 by osmosis, they shortly pass into a resting condition apparently similar to that 

 produced by the lowering of the temperature. Similar results were obtained 

 with Spirogyra threads. The author concludes that these experiments indicate 

 that lowering the temperature causes the cell to lose water. 



In the second paper the results of experiments on the effects of low temper- 

 ature on Asterias are reported. It was found that an exposure to a temperature 

 of from 4°-7° C. during one to nine hours will cause fully maturated but unfer- 

 tilized eggs of the starfish to develop into swimming larvae. Raising the tem- 

 perature failed to cause segmentation. r. p. 



Dewitz, J. Orientining nach Himmelsrichtun- This paper discusses a collection of 

 f "'89-10''' ^" '^''^^' ''•^^y''°'- A'^th. 1901. jjata taken principally from "Ornis" 



on the precise directions taken by birds 

 in their migration flights. It appears from the statistics given that there is a 

 marked tendency for birds to orient exactly towards cardinal points, rather than 

 to proceed along intermediate courses. For example, in the spring more birds 

 fly due north than either northeast or northwest. There is apparently a positive 

 rheotaxis of birds to the wind currents, as more fly in a given direction when the 

 wind is coming from that direction than would under other conditions. 

 The spatial orientations and "sense of direction" of other organisms are briefly 

 discussed. r. p. 



