112 



SCIENCE 



[N. S. Vol. XXXVII. No. 942 



below 0.2 per cent, little or no effect was ob- 

 servable. 



Higher concentrations of ether give a very 

 diilerent result. With 3 per cent, by volume 

 of etlier the resistance rises very rapidly to a 

 maximum (which is about the same as when 

 1 per cent, is used) and then falls very 

 rapidly. But instead of stopping when the 

 normal is reached the resistance continues to 

 fall rapidly until death ensues. If the con- 

 centration of ether be increased the period 

 during which the resistance remains above the 

 normal becomes shorter until finally it be- 

 comes impossible to detect it even when read- 

 ings begin 30 seconds after placing the tissue 

 in the anesthetic. There is a corresponding 

 increase in the rapidity of the fall of resist- 

 ance and of the onset of death. 



The decrease of permeability observed in 

 these experiments may be easily and quickly 

 reversed by placing the tissue in sea water. Is 

 this also the case with the increase in permea- 

 bility ? This was tested in the following man- 

 ner: The material was allowed to remain in 

 the anesthetic until its resistance had fallen 

 about 100 ohms below the normal (i. e., below 

 the resistance it had before being exposed to 

 the anesthetic). It was then replaced in sea 

 water and readings were taken at frequent in- 

 tervals; recovery would be shown by a rise in 

 resistance. 



No such rise in resistance was observed. 

 The experiment was varied by replacing the 

 tissue in sea water after the resistance had 

 fallen only 50 ohms below the normal and also 

 by choosing a concentration of ether which 

 caused the resistance to fall very gradually. 

 Even then there was but rarely any sign of 

 recovery and this was of short duration and 

 small in amount. 



Similar results were obtained with chloro- 

 form, chloral hydrate and alcohol, but not at 

 the same concentrations: the concentrations 

 which correspond to 1 per cent, ether are ap- 

 proximately as follows: chloroform 0.05 per 

 cent., chloral hydrate 0.05 per cent., alcohol 

 3 per cent. 



Two distinct effects are observable in these 

 experiments. One is a toxic effect evidenced 



by an increase in permeability, while the other 

 involves a decrease of permeability. A very 

 important question is, with which of these is 

 the anesthetic action associated? Since the 

 distinctive mark of an anesthetic is the rever- 

 sibility of its action, it is not reasonable to 

 suppose that this action is associated with an 

 irreversible change in permeability. Such a 

 change is in no way peculiar to anesthetics, 

 but is common to all toxic substances. We 

 are, therefore, forced to the conclusion that it 

 is the reversible change, involving a decrease 

 of permeability, which is associated with the 

 anesthetic action. 



The fact that typical anesthetics (ether, 

 chloroform, chloral hydrate and alcohol) de- 

 crease the permeability of the tissue to ions is 

 profoundly significant in view of the fact that 

 the transmission of nervous and other stimuli 

 is believed to depend on the movement of ions 

 within the tissues. W. J. V. Osterhout 



Laboratoky of Plant Physiology, 

 Harvard University 



partial sex-linkage in the pigeon 

 That certain characters in pigeons are sex- 

 linked is shown by the work of Staples- 

 Browne,' Cole^ and Strong." Both Staples- 

 Browne and Strong, however, encountered cer- 

 tain exceptions which I shall try to show are 

 explicable on the assumption that there is in 

 the female pigeon a pair of sex-chromosomes, 

 between which crossing-over of the factors 

 may occur. 



Staples-Browne found that a white female 

 crossed to a dark male produced all dark off- 

 spring, showing that white is recessive to dark. 

 The reciprocal cross, viz., white male by dark 

 female produced dark males and white fe- 

 males. So far, this last cross is a typical case 

 of " criss-cross " inheritance, in which the 

 recessive character entered the cross from the 

 parent homozygous for the sex-differentiating 

 factor, viz., from the male in this case. 



Staples-Browne found, however, in this Y^, 

 in addition to the white females, one dark fe- 



^ E. Staples-Browne, Jour. Genetics, June, 1912. 

 = L. J. Cole, Science, August 9, 1912. 

 "E. M. Strong, Biol. Bull., October, 1912. 



