710 RALPH S. LILLIE 
The faet that the optimum duration of exposure to cyanide- 
containing sea-water is much longer than thirty minutes—in 
fact, several hours—may seem inconsistent with this interpreta- 
tion. Cyanide, however, produces its effect by checking oxida- 
tions and so slowing the entire metabolism of the egg. Hence it 
is not surprising that the chemical processes within the egg proceed 
too slowly in cyanide-containing sea-water to impair the develop- 
mental power, even after a stay of some hours. In hypertonic 
sea-water, on the contrary, oxidations continue unchecked, as 
Loeb as shown; and the condition of the egg undergoes progres- 
sive change of such a kind that return to sea-water within a com- 
paratively brief interval is necessary if normal development is 
to continue. If the oxidations are suppressed during the stay 
in hypertonic sea-water the latter has little or no action; the 
injury normally resulting from a too prolonged exposure to this 
medium is also prevented. 
It should not be overlooked, in considering the mode of action 
of hypertonic solutions, that they appear to increase the rate of 
oxidations in the egg;!7 and although they may do this indirectly 
by altering permeability, there is no direct evidence as yet that 
this is the case. Loeb has found hypertonic sea-water ineffective 
in the absence of oxygen or in the presence of cyanide,!* and 
concludes that the alteration in rate and character of intracellular 
oxidations is the essential change involved. But just how hyper- 
tonic sea-water can modify oxidations remains obscure. The fact 
that it checks or prevents the cytolysis which otherwise succeeds 
the temporary treatment with pure salt-solution has been inter- 
preted above as indicating an action on permeability essentially 
similar to that exerted by calcium in antitoxic action; but I have 
been unable as yet to produce the effects of hypertonic sea-water 
by the use of sea-water containing an increased proportion of 
calcium or magnesium. I have elsewhere adduced evidence 
indicating that anaesthetic or narcotic action is essentially a 
consequence of a decrease in the normal permeability.® If this 
16 Loeb: Chemische Entwicklungserregung, pp. 51 seq. 
17 Warburg: Zeitschrift fiir physiologische Chemie, 1908, vol. 57, p. 1. 
18 J. Loeb: Chem. Entw., also Biochemische Zeitschrift, 1906, vol. 1, p. 183. 
19 Cf. American Journal of Physiology: 1909, vol. 24, pp. 14, 459; ibid., 1910, 
vol. 26, p. 114. At least a decreased susceptibility to increase of permeability must 
