My dear Father,

I ought to have seen the place about Akebia & Stauntonia, also I should think your explanation is quite as good as Sachs, or rather better as it explains the appearance without assuming any new cause.² I had so few Helvingia to work with I couldn’t try whether anything comes out of them.³ Sachs gave me all the berries on the bush but it was too late. The difference in rate of drying is very well marked. Also 3 of the cleaned ones which I have wetted by squirting water over them have mould growing on them. Sachs said they tried some experiments about the growth of mould on fruit, by sowing mould spores on fruit & they found that the mould grow far better on the fruit grapes & apples which has been wiped. He seems to think it very important to make out whether water dissolves anything out of leaves, but he thinks the way of weighing would be no good, as not being delicate enough— He says that if you water a plant with lithium solution & then put the leaves in water the lithium comes out. I have tried here with a tobacco plant & it is quite easy to do & lots of lithium came out.⁴ He thinks it would be a good way of trying cleaned & bloom leaves, though not absolutely convincing as you don’t know whether the lithium is in a natural state in the cell sap.

He says he has found dew alkaline which he supposes is from the potash coming out, & thinks that also worth trying. I had thought of the lithium way with bloom & cleaned, but thought it too imaginary a way. He suggests a a way of testing whether nitrogenous stuff comes out, to infect the water in which cleaned & bloom leaves have soaked with a drop or two of bacterial fluid.⁵ I wish I had thought of this before, as I have had very little to do for the last 10 days & I might have tried it. There is a wild Lactuca here that has leaves which slew so that the edges are up & down a vertical as they grow up, I find it has nearly as many stomata on the upper as on the lower side like an Australian tree.⁶ It has bloom on both sides. I will bring some seed as it might do for comparison somehow with sleepers as its leaves are vertical. I think one might test the nitrogen in water from cleaned leaves with Drosera⁷   I have given your message to Sachs & he seemed much pleased & said that he was much obliged, & that Down was the first place he would wish to go to, if he manages to come through London⁸

I suppose you have got my letter saying I shall be at Leith Hill Thursday afternoon—⁹

Yr affec. | F. D.