574 TEE POPULAR SCIENCE MONTHLY 



believe when we bear in mind that the egg may be caused to develop 

 by short exposure to carbonic acid. On fertilization this hypothetical 

 substance would be liberated and could be collected. Glaser fertilized 

 quantities of eggs in a small amount of sea water. On using the same 

 water in which to develop other fertilized eggs, he found it inhibited 

 their development, indicating the presence of an inhibiting substance 

 that came out of the first eggs on fertilization. (Was this CO,?) 



•Loeb's "improved method of artificial parthenogenesis" claims two 

 treatments of the eggs to be necessary. They are first to be stimulated 

 to development by use of fatty acid, or some other method, and then 

 exposed to a hypertonic solution. The latter he calls a "corrective 

 agent" and supposes that it changes the character of the oxidation in 

 the egg, since he observes no effect on the rate of oxidation in the devel- 

 oping eggs. It is hard to conceive of such a change in "character," 

 since oxidation means union with oxygen and there is but one kind of 

 oxygen atom in combinations. The oxygen might attack different sub- 

 stances, but in such cases different amounts of heat would be given off, 

 the heat of combustion of fats and carbohydrates, for instance, differing 

 in amount. Meyerhof showed that the ratio of oxygen used to heat 

 produced was the same for eggs in the hypertonic solution as in sea 

 water. When we consider that by the use of either fatty acid or hyper- 

 tonic solution alone, sea-urchin {Arhacia) eggs may be made to de- 

 velop, it seems unnecessary to devote more time to their combined effect. 



Eelation of Anesthesia to Development of the Egg 



Anesthetics have a depressant action on various cell activities when 

 used in certain concentration. They decrease the respiration and rate 

 of cleavage of sea-urchin eggs (and asphyxiation will cause cleavage to 

 cease). It may therefore be supposed that it is the suppression of oxida- 

 tion by anesthetics that suppresses cleavage. Warburg, however, caused 

 the almost complete cessation of cleavage in sea-urchin eggs with anes- 

 thetics without appreciably lowering the respiration. It may be that 

 the anesthetic acts in one part of the cell (on the surface of the gran- 

 ules) in suppressing oxidation, and in another (on the cell surface) in 

 suppressing cleavage. 



In 1909, while measuring the electric conductivity of sea urchins' 

 eggs, the writer observed the decrease in conductivity on the addition 

 of a certain per cent, of chloroform. This experiment was not repeated, 

 but we may imagine that the chloroform decreased the permeability of 

 the eggs to ions. Osterhout, becoming interested in the methods used, 

 modified them for use with plants, and observed a decrease in electric 

 conductivity of certain plants (kelp) when using a certain concentra- 

 tion of anesthetic, indicating that the anesthetic decreased permeability. 

 E. Lillie found that anesthetics might antagonize the action of the pure 



