My dear M^r. Darwin

I hasten to send you such information as I can with reference to the various substances which may be found in the cells of plants, though I fear I can tell you very little that will apply to this particular case—² I cannot but think that the granules in question must be derived from the protoplasm, that is, that they must be proteids— If they consisted simply of coagulated latex they ought to be produced as well by pure water as by the dilute carbonate of ammonia—and they ought not to dissolve in water or in dilute glycerin— The question is, are they the result of the contraction of the parietal protoplasm, or are they due to the chemical change of some part of the protoplasm? Is the whole phenomenon a purely physical or a chemical one— In the first case the phenomenon would be simply what de Vries calls “plasmolysis”—that is a contraction of the “primordial utricle” under the influence of the salt,³—and the cell would, in this case, be readily restored to its normal condition by washing out the salt with water— In the second case, it might be assumed that a portion of the protoplasm becomes altered under the influence of the salt, so that it is now soluble in water or dilute glycerine— A substance of this kind is present in many aleurone-grains of seeds—and it appears to be closely allied with the peptones.⁴

If I understand you rightly you say that the substance dissolves in a mixture of glycerin & water— It would be well to ascertain if it disappears on treatment with water alone—

I am very sorry that I can give you no more than these general indications but I will try and observe the thing myself and then I shall perhaps be able to make some suggestion which will be more valuable than anything that I have been able to say here—

The great difficulty is to account for the limitation of the phenomenon to certain cells— If it occurred in all, it would doubtless be more easy to hazard some explanation which might suggest useful reagents.

yours faithfully | Sydney H. Vines