October 20, 1916] 



SCIENCE 



575 



In his paper of 1905 the writer pointed out 

 already that ZnS0 4 retards the injurious ac- 

 tion of a m/2 or 5/8 m solution of NaCl upon 

 the embryo inside the egg, while the newly 

 hatched fish dies more rapidly in a m/2 or 

 5/8 m E~aCl solution when a trace of ZnS0 4 is 

 added; and that this fact was only compre- 

 hensible on the assumption that the antag- 

 onistic action of the ZnS0 4 in the former case 

 was due to an action of this salt upon the 

 membrane, whereby the rate of diffusion of 

 the NaCl through the membrane was di- 

 minished. 



When we put eggs of Fundulus from six to 

 ten days old into a 3 m !NaCl solution the em- 

 bryos are killed and coagulate inside of five 

 hours, for the reason that in this concentration 

 the NaCl is able to diffuse through the mem- 

 brane, which is practically impermeable to 

 water as well as to balanced salt solutions of 

 not too high a concentration. When we add 

 1 c.c. 10/8 m CaCl, to 50 c.c. 3 m IsTaCl, the 

 embryo will keep alive (as indicated by the 

 continuation of heartbeat, circulation, and 

 spontaneous motions of the whole embryo) for 

 from three to five days. 2 This prolongation 

 of life through the addition of Ca is due not 

 to an action upon the protoplasm but to a pre- 

 vention of the diffusion of the NaCl into the 

 egg, since if we take the embryo out of the egg 

 (or use the newly hatched embryo) it is killed 

 in 50 c.c. 3 m NaCl + 1 c.c. 10/8 m CaCl 2 in- 

 side of a few minutes. The antagonistic effect 

 of the CaCl, consisted therefore in this case in 

 the Ca modifying the egg membrane in such a 

 way as to retard the diffusion of NaCl through 

 the membrane. Since the objection might be 

 raised against this conclusion that a slow dif- 

 fusion of Ca into the egg counteracted the 

 effects of an almost equally slow diffusion of 

 NaCl upon the fish itself, we may add that the 

 experiment succeeds just as well if the CaCl 2 

 is replaced by MnCh, which is not • able to 

 counteract the injurious action of NaCl upon 

 the embryo outside the egg, while it counter- 

 acts the injurious action of EaCl upon the 

 embryo while the latter is inside the egg. The 

 antagonistic action of Ca or In or ZnS0 4 (or 



2 Loeb, J., Biochem. Ztschr., 1912, XL VII., 127. 



any salt with bivalent cation) upon the in- 

 jurious action of a NaCl solution consists, 

 therefore, in the case of the egg of Fundulus, 

 purely in the prevention or retardation of the 

 diffusion of NaCl through the membrane of 

 the egg. 



KC1 is a general nerve and muscle poison 

 and causes cessation of the heartbeat in com- 

 paratively low concentrations. When we put 

 the eggs of Fundulus, after heartbeat and cir- 

 culation are established, directly from sea- 

 water into m/8 KC1 the hearts stop beating in 

 a few hours. If, however, the m/8 KC1 solu- 

 tion is made up in m/1 ISTaCl + CaCl, the em- 

 bryo may live in the solution for ten days or 

 more. That we are dealing in this case of an- 

 tagonism also with a diffusion phenomenon is 

 made certain by the fact that the combination 

 !N~aNO s -(- MnCL, is practically as good an an- 

 tagonist against KC1 as is NaCl -f- Cad,, as 

 long as the embryo is in the egg; while when 

 it is out of the egg the mixture NaN0 3 -f- 

 MnCl 2 (as well as NaNO E or MnCl 2 alone) is 

 unable to antagonize KC1. 



These examples, to which many others might 

 be added, show that the phenomena of antag- 

 onism described by the writer for the egg of 

 Fundulus are purely diffusion phenomena and 

 due to a direct action of the salts on the mem- 

 brane of the egg and not due to an action of 

 the salts upon the protoplasm of the embryo. 



2. The experiments on the egg of Fundulus 

 give us therefore an unusual advantage, inas- 

 much as they allow us to decide with certainty 

 whether the phenomena of antagonism are dif- 

 fusion phenomena or phenomena due to the 

 action of salts upon the protoplasm; since we 

 can easily separate the protoplasmic part of 

 the egg — the embryo — from the membrane. 

 On account of this unusual advantage the 

 writer has made this object the basis of his 

 work on the theory of physiologically balanced 

 solutions. When we deal with cells whose 

 membranes we can not remove at desire we 

 have a reason to doubt whether or not the phe- 

 nomena of antagonistic salt action are also of 

 the order of diffusion phenomena. The ob- 

 servations of the writer on the fish itself seem 

 to indicate that phenomena of diffusion enter 



