My dear Sir

I am very much obliged to you indeed for your very kind letter and for the invitation to go to see you.¹ What should I like better, than to do this? But at the same time I hear with greatest sympathy, that your health is weak and that you must avoid excitements of all kind.² I am afraid therefore, that, what would give me not only greatest pleasure, but would be a matter of greatest scientific and mental interest to me, namely to call upon you and make your personal acquaintance, would be a fateague to you, nay even more, would be perhaps a real injury to your health. Therefore I must at present consider it rather unfair, to decide already now upon my accepting your kind invitation. It will be time enough to do so, when I have come to London and after having met our common friend Dr. J. D. Hooker; may he decide, whether it is possible, that I may go to see you, without injury to your precious health, which God the strengthen, that you are long still kept to your family, your friends and to science.³ The scientific congress is badely off, that you are unable to partake of it.⁴

I regret much that just 10 years ago, when I was for the last time in England, I did not follow the advice of your friend Dr. Hooker to go and see you— But having in sight at that time the finishing of a peculiar object and being very short of time, I could not follow Hooker’s advice.

Now, my dear Sir, do all in your power to strengthen your health, avoid every, even little thing, which weakens it. May your health be spared to finish as much, of the scientific objects, the elaboration of which you have in hands, as possible— These wishes, I should say rather prayers I have the warmer for you, as I have the same in a similar case in my own family. My father in law Prof. Alex. Braun, whose signification in science you know as I,⁵ is also in very poor health for months, although his suffering is rather an acute one from repeated colds, which he caught. But he can not recover now and continues to be very feable, having not left the bed for weeks. This state seems to me the more dangerous, as he suffers from colds each winter, and in the last winters really severely.

With sincerest regard, believe me, my dear Sir, yours very faithfully | Rob. Caspary