arises from the internal structure of their parts, which incapacitates them for incubation. According to this gentleman, the crop, or craw, of a cuckoo, does not lie before the sternum at the bottom of the neck, as in the gallina, columbæ, &c., but immediately behind it, on and over the bowels, so as to make a large protuberance in the belly.*

Induced by this assertion, we procured a cuckoo; and, cutting open the breast-bone, and exposing the intestines to sight, found the crop lying as mentioned above. This stomach was large and round, and stuffed hard, like a pincushion, with food, which, upon nice examination, we found to consist of various insects, such as small scarabs, spiders, and dragon-flies-the last of which we have seen cuckoos catching on the wing, as they were just emerging out of the aurelia state. Among this farrago also were to be seen maggots, and many seeds which belonged either to gooseberries, currants, cranberries, or some such fruit; so that these birds apparently subsist on insects and fruits; nor was there the least appearance of bones, feathers, or fur, to support the idle notion of their being birds of prey.+

The sternum in this bird seemed to us to be remarkably short, between which and the anus lay the crop, or craw, and immediately behind that the bowels, against the backbone.

It must be allowed, as this anatomist observes, that the crop, placed just below the bowels, must, especially when full, be in a very uneasy situation during the business of

quantity of food; to obtain which they must, like the swallow, be in constant search of it. If they sat on their eggs, therefore, how is this necessary supply to be obtained? The eggs would be chilled while they were on the wing.-ED.

*Histoire de l'Academie Royale, 1752.

When these birds have fed much on some of the large hairy caterpillars so common on the northern muirs, the stomach becomes filled and coated with the short hairs, which may have assisted in raising the opinion that they feed on small animals.-W. J.

"The cuckoo," Mr. Owen says, has no true crop, and the situation of its proventiculus does not differ from that of other scansorial birds; the œsophagus descends along the posterior or dorsal part of the thorax, inclining to the side, and, when opposite to the lower margin of the left lung, it begins to expand into the glandular cavity or proventiculus. The gizzard, which is neither large or strong, is in immediate contact with the abdominal parietes, not separated from them by an intervening stratum of intestines;

incubation; yet the test will be, to examine whether birds that are actually known to sit for certain, are not formed in a similar manner. This inquiry I proposed to myself to make with a fern-owl, or goat-sucker, as soon as opportunity offered; because, if their information proves the same, the reason for incapacity in the cuckoo will be allowed to have been taken up somewhat hastily.

Not long after, a fern-owl was procured, which, from its habits and shape, we suspected might resemble the cuckoo in its internal construction. Nor were our suspicions ill grounded; for, upon the dissection, the crop, or craw, also lay behind the sternum, immediately on the viscera, between them and the skin of the belly. It was bulky, and stuffed hard with large phalana, moths of several sorts, and their eggs, which, no doubt, had been forced out of these insects by the action of swallowing.

Now, as it appears that this bird, which is so well known to practise incubation, is formed in a similar manner with cuckoos, Monsieur Herissant's conjecture that cuckoos are incapable of incubation from the disposition of their intestines, seems to fall to the ground; and we are still at a loss for the cause of that strange and singular peculiarity in the instance of the cuculus canorus.

We found the case to be the same with the ring-tail hawk, in respect to formation; and, as far as I can recollect, with the swift; and probably it is so with many more sorts of birds that are not granivorous.

LETTER LXXIII.

TO THE SAME.

SELBORNE, April 29, 1776.

DEAR SIR,—On August the 4th, 1775, we surprised a large viper, which seemed very heavy and bloated, as it lay in the grass, basking in the sun. When we came to cut it up, we found that the abdomen was crowded with young, fifteen in

but this position cannot be supposed to interfere with the power of incubation, since it occurs also in other birds that do incubate, as the owl and Caryocatacles."

number; the shortest of which measured full seven inches, and were about the size of full-grown earth-worms. This little fry issued into the world with the true viper spirit about them, showing great alertness as soon as disengaged from the belly of the dam: they twisted and wriggled about, and set themselves up, and gaped very wide when touched with a stick, showing manifest tokens of menace and defiance, though as yet they had no manner of fangs that we could find even with the help of our glasses.

To a thinking mind, nothing is more wonderful than that early instinct which impresses young animals with the notion of the situation of their natural weapons, and of using them properly in their own defence, even before those weapons subsist or are formed. Thus a young cock will spar at his adversary before his spurs are grown, and a calf or lamb will push with their heads before their horns are sprouted. In the same manner did these young adders attempt to bite before their fangs were in being. The dam, however, was furnished with very formidable ones, which we lifted up (for they fold down when not used), and cut them off with the point of our scissors.

There was little room to suppose that this brood had ever been in the open air before,* and that they were taken in for refuge, at the mouth of the dam, when she perceived that danger was approaching; because then, probably, we should have found them somewhere in the neck, and not in the abdomen.

*The very circumstance which Mr. White mentions, of the young vipers being fully seven inches in length, proves that they had been in the open air before, as they have been known to leave the stomach of the dam when they have been from one to two inches in length. From various facts communicated to me by viper-catchers and others, I can have no doubt but that the young vipers, when alarmed, take refuge in the inside of the parent, who extends her mouth for the purpose.-ED.

LETTER LXXIV.

TO THE SAME.

CASTRATION has a strange effect: it emasculates both man, beast, and bird, and brings them to a near resemblance of the other sex. Thus, eunuchs have smooth unmuscular arms, thighs, and legs; and broad hips, and beardless chins, and squeaking voices. Gelt stags and bucks have hornless heads, like hinds and does. Thus wethers have small horns, like ewes; and oxen large bent horns, and hoarse voices when they low, like cows: for bulls have short straight horns; and though they mutter and grumble in a deep tremendous tone, yet they low in a shrill high key. Capons have small combs and gills, and look pallid about the head like pullets; they also walk without any parade, and hover chickens like hens. Barrow-hogs have also small tusks, like sows.

Thus far it is plain, that the deprivation of masculine vigour puts a stop to the growth of those parts or appendages that are looked upon as its insignia. But the ingenious Mr. Lisle, in his book on husbandry, carries it much further; for he says that the loss of those insignia alone has sometimes a strange effect on the ability itself. He had a boar so fierce and venereous that, to prevent mischief, orders were given for his tusks to be broken off. No sooner had the beast suffered this injury than his powers forsook him, and he neglected those females to whom before he was passionately attached, and from whom no fences could restrain him.t

*This is not the case if the spermatic cord has been separated. It equally emasculates the animal, but the horns remain as before the operation.—ED.

+ I apprehend this remark to be erroneous, as I have known the tusks of many dangerous boars sawn off, for safety, without any such consequence following. I have seen them, however, no longer able to command the monopoly of the sows, as the young boars were no longer afraid of them. -MR. SELLS.

LETTER LXXV.

TO THE SAME.

THE natural term of a hog's life is little known, and the reason is plain-because it is neither profitable nor convenient to keep that turbulent animal to the full extent of its time; however, my neighbour, a man of substance, who had no occasion to study every little advantage to a nicety, kept a half-bed Bantam sow, who was as thick as she was long, and whose belly swept on the ground, till she was advanced to her seventeenth year; at which period, she showed some tokens of age by the decay of her teeth, and the decline of her fertility.

For about ten years, this prolific mother produced two litters in the year, of about ten at a time, and once above twenty at a litter; but, as there were near double the number of pigs to that of teats, many died. From long experience in the world, this female was grown very sagacious and artful. When she found occasion to converse with a boar, she used to open all the intervening gates, and march, by herself, up to a distant farm where one was kept; and, when her purpose was served, would return by the same means. At the age of about fifteen, her litters began to be reduced to four or five; and such a litter she exhibited when in her fatting-pen. She proved, when fat, good bacon, juicy and tender; the rind, or sward, was remarkably thin. At a moderate computation, she was allowed to have been the 'fruitful parent of three hundred pigs—a prodigious instance of fecundity in so large a quadruped! She was killed in spring, 1775.