138 Mr. E. Whitley. Effect of Acid, etc., on [Nov. 14, 



The accelerating effect of small quantities of alkali on growth observed by 

 Loeb in the case of Tubularia,* and the eggs of Arbacia.f and in those 

 of Echinus, in the research mentioned above, was not noticed, but attention 

 may be drawn to the very powerful results of even a small disturbance of the 

 chemical equilibrium, which can be seen from Table I, where it will be 

 observed that, after six days, 4 c.c. of decinormal acid or alkali in 200 c.c. of 

 sea-water (i.e., a five-hundredth normal solution) produces a death-rate among 

 fresh eggs of 75 and 44 per cent, respectively, against only 5 per cent, in the 

 Control. 



In the experiments above alluded to with the eggs of Echinus esculentits, it 

 was found that acids and acid salts above a very small concentration pro- 

 duced more deadly effects than corresponding quantities of alkalies and 

 alkaline salts, and this was also found to be the case with Pleuronectes, 

 and can be well seen in the same table (I) for strengths of 2'5 c.c. and 

 upwards, especially with the younger eggs. 



Probably three factors enter into the explanation : — 



(1) The fact that part of the alkali added is immediately thrown out 

 of solution as insoluble hydrates or carbonates. 



(2) Alkali is constantly being used up to neutralise the acid products 

 of metabolism — chiefly CO2. 



(3) According to Loeb, the presence of weak alkali assists the absorption of 

 oxygen by the organism. If this be the case, the eggs in the acid solutions 

 not being able to absorb oxygen so readily as the others, might probably 

 be less resistant to the action of the reagent. 



The tables seem also to show conclusively that the younger eggs are 

 far more sensitive to the action of the acid or alkali, and generally to 

 the influences of their environment than are the older eggs, or newly-hatched 

 larvae, which are, indeed, extraordinarily resistant. Thus, on referring again 

 to Table I, it will be seen that a very large percentage of the older eggs 

 survived 7, and even 11, days' treatment, whereas, of the fresh eggs, over 

 25 per cent, in the Control, and a much larger number in all the other cases 

 were dead within 10 days. In this table the effect only of very small 

 quantities of acid or alkali is given (five-hundredth normal and under), but 

 experimentation with somewhat larger amounts gave the same result as shown 

 in Table II. Thus, it needed only 6 c.c. of decinormal sodium hydrate to kill 

 all the fresh eggs in four days, but more than 8 c.c. to kill all those of two 

 days old in the same time, while, by the end of that period, 30 c.c. of alkali 



* ' Univ. of California Publications, Physiol.,' vol. 1, 1904, p. 137, and ' Arch. f. gesant. 

 Physiol.,' vol. 101, 1904, p. 340. 



t ' Arch. f. Entwickelungsmechanik,' vol. 7, p. 631. 



