From Jeffries Wyman [c. 15] September 18601
During the frequent conversations I have had with our mutual friend Prof Gray, on the Origin of Species, he has sometimes expressed a wish that I would communicate to you such views as I might have on the subject.2 Entertaining the belief that progressive development is a far more probable theory than progressive creations, I have no desire to trouble you with any notions of my own; for I am sure after all the varied discussions, fair & unfair, which your work has called forth in Journals & Societies, anything I might say would prove superfluous. I think science owes you a huge debt, if for nothing else, for reopening the question in such a masterly manner as to create an universal interest in it both among scientific men & others. My object in writing is only to say a few words on one or two unrelated points, for which I trust you will excuse me
First of all however permit me to state, that having some 18 months since made an excursion to the Uruguay La Plata & Parana rivers, also across the continent to Valparaiso, how much indebted I am to you for the pleasure, instruction & assistance derived from the “Journal of a Naturalist”,3 which served me as a guide book, wherever my route was the same with yours.— Among the subjects which interested me very much was your description of the Nãta, the curious breed of cattle with imperfectly developed upper jaw.4 I do not see that you mention it in the Origin of Species, though it seems to me a good instance of a monstrosity becoming transmissible like that of the “otter breed” of sheep Manx cats, Dorking fowls &c. After numerous enquiries I suppose there can be no doubt that it is a breed.
What gave me especial interest in it however was, that several years since during an excursion to Labrador I found that a similar monstrosity was occasionally met with in the Cod fish & is sufficiently common to be known among fishermen as the “bull dog cod”. I procured two specimens of it & prepared the heads which present deviations analogous to those of the nãta, viz an arrest of the development of the upper jaw. Among the things brought with me from S. America was the skull of a nãta, which shows very well its osteological peculiarities.5
I believe Prof Gray communicated to you a statement by me, in regard to the effect of the “paint root” on the Hogs causing the hooves of all but the black varieties to drop off.6 I have every reason to believe the statement true not only from information which I obtained myself when in Florida, but from further enquiries made by Dr A. S. Baldwin of Jacksonville in that state;7 who informs me that it is not only generally believed but practiced upon. & as one of the “Crackers”, (ie a Florida squatter) remarked to me, we “select” the black members of a litter for raising as they alone have a good chance of living.8
I was rather sorry to find that the cows living in the swamps did not manifest any additional length of legs as Audubon & Bachman assert that the Deer do, when compared with those living on high grounds.—9
In the Origin of Sps. you refer to the “rat” from Mammoth cave as illustrating the influence of the absence of light in modifying the eyes. In this case I believe you have been led into an error by Prof Silliman.10 Prof Baird who is well informed on the subject, & eminently qualified to judge of the matter, tells me that the animal in question is not the Norway rat but belongs to another genus viz the Neotoma, the eyes of which are naturally of larger proportions than those of the Norway rat.11 It is doubtful therefore whether any change has taken place in them.
In connection with the above I would also refer to what you say in regard to our old friend the tucu-tucu. (Ctenomys.)12 Would not the blindness be explained in that case in some other way than as the result of accidental injury? I believe it is generally admitted by physiologists that the effects of mechanical injuries are not transmitted by inheritance & in view of the fact that the Jews after so many centuries of mutilation persist in being born with a prepuce, I am inclined to believe it. Is it not the persistence of an embryonic condition? All mammals go through a certain formality as regards their eye lids; viz. after the lids begin to grow they advance towards each other, meet, & adhere quite firmly; after having remained in this condition for a certain time variable in different species they open again, in some before birth as Rumnts & Pachyderms, sometimes about the time of birth, as in Man & Monkeys, & in others not till several days after as in Rodents & Carnivore. The Russian Rat mole (Spalax) never opens them but retains through life the adhesive stage of the embryonic condition. I never had the good
Cases of monstrosities becoming transmissible.
Comments on passages in Origin on the blindness of the tucu-tucu (Ctenomys) and Mammoth Cave rats.
Please cite as
Darwin Correspondence Project, “Letter no. 2901,” accessed on 25 August 2016, http://www.darwinproject.ac.uk/DCP-LETT-2901