The Zoological Garden has only one old adult male of Limulus. When there were females, eggs were never observed.
Encloses a separate letter  about AD’s scheme [for a zoological station].
Suggests AD be cautious [in his work]. “Caution is almost the soul of science.”
Down. | Beckenham | Kent. S.E.
Jan 4 1870
My dear Sir
On the receipt of your letter I wrote at once to the Director ofour Zoolog. Gardens, about the Limulus.f1 He informs me that theynow have only one old adult male; but when they had both sexes eggswere never observed. Your best chance wd be to write to someZoologist on the shores of the United States; I cannot help youin this, as my sole correspondent, Dana,f2 is now much out of health.
I enclose a separate letter about your scheme, which has my goodwishes; but I am sure that you estimate my influence & judgment muchtoo highly. The opinion of naturalists who have visited the coast forsome special investigation wd be worth far more than mine. I fearyour plan will cost you much loss of time in writing letters & makingarrangements. I wd suggest to you to delay attempting so great anaddition as the formation of a scientific library.
Lastly let me thank you for your very kind & strong expressions towardsmyself, & for your information with respect to your present views onembryology.
Forgive me for suggesting one caution; as Demosthenes said,“action, action, action” was the soul of eloquence, so is cautionalmost the soul of science.f3
Pray bear in mind that if a naturalist is once considered, though unjustly,as not quite trust worthy, it takes long years before he can recover hisreputation for accuracy.
Pray forgive me for this caution. You ask about my health; I cannotsay much in its praise, but as long as I live the life of a hermit I amable to work some hours daily.
With the most sincere good wishes | I remain my dear Sir | yours veryfaithfully | Ch. Darwin