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Animal Physiology: the late Mr. Chas. Darwin.

I SHOULD feel happy to write, in compliance with your gratifying request, something regarding my acquaintance with the great naturalist, Mr. Charles Darwin, and the subjects which I discussed with him, but that, in approaching the task, a serious difficulty is presented to me. I see that I shall be compelled to say much about myself—a very objectionable and unpleasant thing—but as it is inevitable in relation to the writing of this paper, which must deal with the reasons which induced me to seek the acquaintance of the great philosopher, I trust I shall not be charged with a desire to be egotistical.

The first and chief subject which it was my privilege to discuss with Mr. Darwin was in relation to in-and-in breeding of Shorthorns, and this was one to which I had myself for years devoted much attention, having closely watched the results obtained from that system of breeding when opportunity offered.

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In this remarkable production, Mr. Darwin says at once that the prevention of free crossing and the intentional matching of individual animals are the corner stones of the breeder's art; but he adds, that, with the evidence before him, he is convinced that it is a great law of nature that all organic beings profit from an occassional cross with individuals not closely related to them in blood; and that, on the other hand, long continued inbreeding is injurious. He was aware that through the whole organic world elaborate provision had been made for the occassional union of distinct individuals.

Mr. Darwin knew that close interbreeding may with some animals be carried on for a considerable period with impunity by the selection of the most vigorous and healthy individuals, but sooner or later evil followed; the visibility of the ill effects was not in such cases readily recognised, because the deterioration was gradual.

It will thus be seen that there were at the same time put before the world the conflicting opinions, upon the subject of breeding; Mr. Richard Booth, the owner of the great herd, and of Mr. Darwin, one of the greatest of naturalists. Fully agreeing with Mr. Darwin's views, which coincided with the knowledge acquired in my experience, I felt anxious to give him the results of my observation. I wrote to him in the autumn of 1873, enclosed a copy of the little treatise I had written in the preceding year, expressed my adhesion to his views and my desire to visit him, so that I might have from himself his opinions upon various points, and that I might put before him what I knew of the injurious results of long continued close-breeding in Shorthorns.

In his reply, Mr. Darwin said: "I have been much gratified by your letter; it is in the highest degree satisfactory to me to find that a man with such large experience as yourself agrees with what I have deduced to a considerable extent." He invited me to visit him at his home in Kent—Down, a secluded retreat, four miles from Orpington Station; although within an hour of London, it was quite a place far from the madding crowd, and suitable for the enjoyment of study and contemplation.

The day was appointed for the visit, and in October, 1873, I found myself in the home of the great naturalist, quietly discussing the then burning question of close breeding in Shorthorns.

The genial presence, the modesty and simplicity of manner of this wonderful man were very remarkable. "I could not think," he said, "it would be worth your while to lose a day in London for the sake of having a talk with me."¹ This was a modest tone to be assumed by one who was not able on one occasion to make it convenient to be at home to see the Emperor of Brazil, who was anxious to visit him, and who had done a good deal in the way of assisting scientific researches in his own country.

¹ This is a quote from Darwin to Downing 20 October [1873]. Correspondence vol. 21, p. 457.

Mr. Darwin had the art of making a stranger speedily at ease, and he at once proceeded to discuss with me the matter of consanguineous relationships. He mentioned that his deductions as to the evil results of close breeding had been combated by some who said that he was a mere theorist, but that they, practical men who had long experience in breeding cattle, differed from him. He was particularly pleased when I explained that there was at the time a certain fashion prevalent and that this fashion insisted upon what was termed "pure" blood.

I also told him that I had known barrenness and abortion to have been frequent in some closely-bred herds, that cases of blindness came to my knowledge, and that I had seen calves got by a bull—much in-bred—from cows related to him, which were affected with brain disease so badly that they were slaughtered while very young. The calves from cows by the same sire, but not related to him, were not so affected. He had heard of pigs born idiotic and without sense even to suck, and when attempting to move they could not walk straight. I gave instances of consumptive tubercular disease, which came under my observation. The animals were very closely bred, and for some years looked healthy, but when the disease had attained a certain height, they rapidly broke up and died. I saw their lungs, which were very much perforated with tubercles.

In "Animals and Plants" Mr. Darwin had stated that animals may seem robust, but yet may be unfertile from in-and-in-breeding, and he was anxious to know if I had seen such cases, to which question I was able to reply in the affirmative.

But perhaps there was nothing upon which he spoke with such lively interest as proving the value of the infusion of a fresh element, as the result of a trial with plants which he had not very long since made. One plant was fertilised by pollen from the same flower, the other by pollen from a distinct plant of the same variety. He did not expect that the results would exhibit any remarkable difference, but, to his astonishment, the young seedlings from the latter or crossed seed were twice as tall as the seedlings from the self-fertilised seed, both seeds having germinated on the same day.

This striking result surprised him. Indeed, it seemed to him incredible that such a result could be due to a single act of self-fertilisation, and it was only in the following year, when precisely the same result occurred in the case of a similar experiment, that his attention became fixed upon it, and that he regarded it as of great importance. Until then he had always supposed that no evil effects would be visible until after several generations of self-fertilisation, but now he saw that one generation sometimes sufficed to make a great difference, and the existence of dimorphic plants and all the wonderful contrivances of orchids were quite intelligible to him. He afterwards published his book on "The Effects of Self and Cross Fertilisation," the result of eleven years of experimental work.

At the time of my visit to Down Mr. Darwin's health was by no means good. He had lately been ill, and his doctor urged him not to excite himself by much conversation. If he did so his rest at night would be disturbed; but he was able to do a good deal of scientific work in his study free from any excitement. For the past thirty years he had not enjoyed real health, and yet what work he had accomplished!

Before leaving, in the afternoon, I promised to send Mr. Darwin two letters which I had written in Bell's Messenger, one upon "Fashionable Breeding," and the other upon "Type Maintenance," as well as some manuscript notes on certain of the points which we had discussed.

I had the satisfaction to receive from him this letter:—

"Down, October 25th.

"My dear Sir,—Your two letters in Bell's Messenger strike me as quite excellent, and I have read them and your MS. notes (for which I am greatly obliged) with the highest interest. I enjoyed my conversation with you, and it has done me no harm. Heartily wishing you all the success you deserve,

"I remain, my dear Sir,

"Yours faithfully,

"C. DARWIN.

"I have copied the conclusions to your second letter."

[The remainder is not transcribed but may be read in the images or the PDF.]

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Animal Physiology: the late Mr. Charles Darwin.

(Continued from page 534.)

II.

BREEDING FOR SEX.

The theories upon this subject are many, most of them old, some new. It is said that 500 theories have been advanced in relation to the development of sex in human beings, and the most generally supported would appear to be the "ovulary," which makes sex an inherent quality in each ovum; the "spermatic," which refers it to the influence of the sire; and the "superiority" theory, which is strongly supported, maintains that the stronger parent at the time of copulation asserts the determining influence.

Some French flockmasters, many years ago, carried out experiments by mating young rams with old ewes, and vice versa. Again, it has been asserted that the period of heat at which service occurs determines the sex, and many have expressed their belief that food has

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an effect upon the conception. Some breeders have found a young bull to get chiefly males, while the experience of others has been quite the reverse.

There have been a good many amateur experimentalists on the subject who easily convinced themselves that their views were the only correct expositions of this feature of nature.

It appears, however, pretty clear that most of those who have given attention to the matter had in their minds that after impregnation the sex was established, so to speak, ab initio.

I had some correspondence with Mr. Darwin in 1874, when I put before him several letters written by men of intelligence who held certain of these views. He wrote to me, "Many thanks for the sight of the enclosed letters. It is, I believe, an error to speak of the ovules or the spermatozoa as being of any sex. There is fairly good evidence that the embryo is at first of both sexes—i.e., hermaphrodite; and that afterwards either the male or female organs abort, leaving the animal of the opposite sex. But what determines the abortion of one or the other sex seems at present unknown, probably it depends on many causes."

If those who, in the future, investigate this question of the control of sex will apply themselves to this one point—the causes of the abortion of one of the sexes in embryo—as to which there is not at present much known, there will be a far greater probability of attaining valuable results than there was by the experiments or trials which have usually been made.

In another letter Mr. Darwin asks, "Do you yourself know of any facts in cattle or other animals showing a tendency to produce either males or females in excess, being inherited or running in the blood?" He thought Lord Spencer had written something on the point, but I could only find an article in the first volume of the Royal Agricultural Society's Journal, which that nobleman contributed "on the gestation of cows." This gives tables comparing the number of days of gestation and the nature of the produce—i.e., whether cow-calves, bull-calves, or twins.

I believe Lord Spencer was anxious to procure information which would assist the cultivation of a heifer-breeding tendency in dairy herds.

In my own experience with Shorthorns, I only know one tribe which regularly bred an excess of females. I acquired it from the late Mr. Jones of Waterford, who had it for forty years, and he assured me that the cows of this Lupine blood had all through been breeding an excess of female produce. Mr. Grove wrote me to say that he knew some Shorthorn families which produced offspring principally of one sex; and the late Mr. Barnes' Mantalinis for a great many years, very much to his disappointment, produced mostly bulls. The result of Mr. Darwin's consideration was given as follows:—"From what you say I think I may venture to assert that occasionally a tendency to produce one sex more than the other runs in certain families of Shorthorns."

Among the last letters which I received from the departed naturalist was one in which he inquires about greyhounds. He said:—"I want information on one simple point. It is whether large breeders of greyhounds rear more dog than bitch puppies? I know that with common breeds of dogs most persons prefer rearing more of the males than of the females, and I want to know how this is with greyhounds. I should like to put the case thus: If one bitch produced a litter of four females and two males, and another bitch produced a litter of four males and two females, how many of each sex (as a general sort of rule) would be reared?"

I sent all the best information which I could glean in reply to those inquiries, and this was the close of my correspondence with the great scientific labourer, whose ashes were some years ago fitly laid in Westminster Abbey, near to the grave of Sir Isaac Newton.

JOHN DOWNING.