54 Arber.—On the Effect of Salts on the Assimilation 
Other similar experiments confirmed this. With regard to 
the duration of the experiments, eighteen days was the limit 
to which any of my cultures with NaCl were carried, and in 
this time I have never observed the maximum of starch 
storage in cultures of this or any other percentage of sodium 
chloride alone . The results with tap-water solutions of Na Cl 
were very similar throughout to those with distilled water ; if 
anything a little more starch was formed. 
Experiments were also made to find the percentage of 
sodium chloride which gave the best results in the way of 
starch-formation, and the effect of dilute and concentrated 
solutions of the same salt. Lesage 1 is among the very few 
writers who have directly estimated the effect of the amount 
of salt (Na Cl) present in the soil on the power of starch- 
formation 2 . Lesage found that the quantity of starch formed 
in the vegetative organs of Lepidinm sativum was directly 
influenced by the amount of sodium chloride present. The 
maximum of starch-formation was reached when the plant 
was watered with a solution containing 2-5-5 grams NaCl in 
a litre. The lower minimum was found to be i-6 grams per 
litre; and the upper, 12-5. grams NaCl in a litre, when no 
starch was formed. Lesage came to the general conclusion 
that the amount of starch decreases as the amount of sodium 
chloride increases, but not in the same degree. Richter 3 
found that many freshwater Algae can be accustomed to 
solutions of sodium chloride, provided the adaptation is not 
too forcible. Plasmolysis was never observed in experiments 
in which the increase in the percentage of the salt was 
gradual and spread over a considerable period. At the end 
of each successive adaptation, i. e. the point at which the 
plant became fully acclimatized, there was a marked increase 
in the amount of starch formed and stored, and this was 
1 Lesage (’91). 
2 A considerable amount of work has been done by Strange (’92), Janse (’87), 
Oltmanns (’95), and others on the effect of concentration of the medium, but the 
standpoint has been almost entirely that of growth and development. 
3 Richter (’92), p. 55 . 
