KOVEMBER 17, 1911] 



SCIENCE 



659 



in the fact that in the mixture of NaCl and 

 CaClj the two salts render their diffusion 

 into the cell mutually more difficult. After 

 a longer period of time the plasmolyzed 

 cells can expand again in a mixture of 

 NaCl and CaClj, but that occurs much later 

 than if they are in the pure NaCl solution. 



These experiments are the analogue of 

 the observation on the embryo of the eggs 

 of Fundulus in which a pure solution of 

 ZnSO^ diffused rapidly through the mem- 

 brane or micropyle, while, if both salts were 

 present, the diffusion was inhibited or con- 

 siderably retarded. 



While the observations of Osterhout show 

 that Overton was not justified in using the 

 experiments on plasmolysis to prove that 

 the neutral salts can not diffuse into the 

 cells, yet they do not prove that these salts 

 diffuse into the cell under normal condi- 

 tions. In Osterhout 's experiments the cells 

 are in strongly hypertonic solutions and it 

 does not follow that such solutions act like 

 isotonic, perfectly balanced solutions. 



Wasteneys and I have recently shown 

 that the toxic action of acids upon Fun- 

 dulus can be annihilated by salts. If we 

 add 0.5 c.c. N/10 butyric acid to 100 e.c. of 

 distilled water these fish die in 2^ hours or 

 less. In solutions which contain 0.4 c.c. or 

 less acid they can live for a week or more. 

 If we add, however, 0.5 c.c. of butyric acid 

 to 100 c.c. of solutions of NaCl of various 

 concentration, we find that above a certain 

 limit the NaCl can render the acid harm- 

 less. It is needless to say that the NaCl 

 used in these experiments was strictly neu- 

 tral and that the amount of acid present in 

 the mixture of acid and salt was measured. 

 The following experiment may serve as an 

 example. 



If the amount of acid was increased, the 

 amount of NaCl also had to be increased to 



2 hours 

 4 hours 



1 day... 



2 days.. 



3 days.. 



4 days.. 



Number of Surviving Fish in 0.5 c.c. JVliO 

 Butyric Acid 



+0 4.0 6.0 8.0 10.0 12.0 15.0 



c.c. m./2 NaCl in 100 c.c. of the Solution 



render the acid harmless. In order to ren- 

 der 0.5 c.c. .A''/10 butyric acid pro 100 c.c. 

 solution harmless, 10 c.c. m./2 NaCl had to 

 be added; while 0.8 c.c. butyric acid re- 

 quired 20 c.c. and 1.0 c.c. butyric acid re- 

 quired about 28 c.c. m./2 NaCl in 100 c.c. 

 of the solution. 



Not only butyric acid, but any kind of 

 acid, could be rendered harmless by neutral 

 salts, e. g., HCl by NaCl. 



It is of great importance that the an- 

 tagonistic action of CaCla was found to be 

 from 8 to 11 times as great or powerful as 

 the action of NaCl. This harmonizes with 

 the general observation that the protective 

 action of CaClj for the life of cells is 

 greater than that of any other substance. 



Wasteneys and I could show that the rate 

 of the absorption of acid by the fish is the 

 same in solutions with and without salt. 

 This proves that the action of the salts con- 

 sisted in this case not in preventing the 

 diffusion or absorption of the acid, but ia 

 modifying the deleterious effect of the ab« 

 sorbed acid. 



We can state a little more definitely the 

 cause of death by acid. If we put the fish 

 into a weak acid solution in distilled water 

 just strong enough to kill the fish in from 

 1 to 2 hours (e. g., 500 c.c. H^G + 2.0 o.o, 

 N/10 HCl), we notice that the acid very 

 soon makes the normally transparent epi- 

 dermis of the fish opaque, and a little latey 

 the epidermis falls off in pieces and shreda. 



