My dear Father,

Just after I wrote last Sachs asked me if I should like to publish my root work in his Arbeiten so of of course I said I should like it.² It is nice to publish with the other people who have been working with me here & there is also honour and glory. It is rather difficult to write as I must not quote the last edition even of the Lehrbuch as there Sachs evidently expected negatively heliotropic roots to grow quicker in light.³ I am glad to discover that he has not been quite so much of a weather cock as I thought as in 1876 his pupil Müller Thurgau published what is pretty well the general idea which we have namely that Heliotropism is not the direct result of the shaded side being obliged to grow quicker but that heliotropism & geotropism are both “Reizerscheinungen”⁴   In his lectures this summer he has said the same thing distinctly—that the light or gravity acting in an unusual direction acts like a Reiz and the plant’s internal organisⁿ. determines what kind of movement shall follow. When Müller Thurgau wrote his paper he quoted what was merely Sachs opinion as if it had been published so that I asked Sachs where he had published this view about Heliotropism. I thought the simplest thing in quoting was to speak of “Müllers investigations in the Lab at Wzbg”: but Sachs wants me to put some such phrase as “The question which Sachs laid before Müller for investigation in the Lab at Wzbg”. Müllers way of putting it is certainly misleading so I suppose I must say something of the kind⁵

He also wanted me to criticise Wiesner, & I was preparing to say I would see him blowed when he took it into his head he would do it himself, which is a relief.⁶ Sachs says he will translate my paper for the Arbeiten into German himself as it is so short. It is usually called purgatory here when an MS has been given to Sachs & until it is quite approved of. Elving the Finn has had an awful dose of purgatory, Sachs wants him to bring in his favourite idea of an organ which grows horizontally really consisting of a positive & negatively geotropic organ tied together, & a lot of other schematic things. Elving and everybody here thinks it pure bosh, & he is trying to bring it to absurdity by inventing more & more such theories & drawing them on the black board & showing them to Sachs; anyhow he says he won’t alter his MS in this respect.⁷ I produced the theory that when a man stands still he only does so because he really consists of two men walking equally quick in opposite directions, which met with much applause from the simple German mind

I shall start on Thursday pm & go by Heidelberg & Strassburg. I want to get one or two things at the instrument maker at Heidelberg & then Strassburg is so close that I should like to go & see D^e Bary & C^o for one day.⁸ I shall be able to get to London by Sunday sometime I hope & so on. I suppose of course Ubbadubba goes with you when you go? If you want me to look at the life of Eras I shall call at Uncle Ras so any message would find me there.⁹ I have made two appeals to the public to know how the dickens to get to Coniston. I can do the French life quite well.¹⁰