Dear M^r Darwin

Let me thank you very much indeed for your most interesting letter.¹ I venture to make one suggestion in respect to the Pinguicula which I fancy at the same time can hardly have escaped you

The seeds of the species of Brassica are very rich in Nitrogen. A familiar illustration of this is the fact that Rape cake (Brassica campestris)² which is the residue after the expression of the oil is employed as a food for cattle and when damaged is even used as a nitrogenous manure. I find on referring to Knop’s tables that Rape seed contains (air dried) nearly 20 per cent of albuminoids³

Believe me | Yours very truly | W. T. Thiselton-Dyer