Since writing the above, another case has occurred in the author's practice. The cow--belonging to Samuel Barton, Esq., near Bordentown, New Jersey--had been in labor some eighteen hours; upon an examination of the animal, the calf was found to be very much deformed, presenting backwards,--one of the hind-legs having been pulled off by the person or persons assisting her previous to the author's arrival. Finding it impossible to deliver her in the usual way, embryotomy was in this instance employed. By this means, after taking out the intestines, lungs, etc., of the _foetus_, and cutting away its hind-quarters, the fore-parts were brought away. The head presented a singular appearance; the under jaw was so twisted as to bring the front teeth on the side of the face; the spinal column or back-bone, was turned twice around, resembling a spiral string; the front legs were over the back; the ribs were much contorted; the hind-parts were as much deformed; and, taken altogether, the deformity was the most singular which has been brought under the author's observation. FREE MARTINS.--It has long been supposed by stockbreeders, that if a cow produce twins, one of which is a male and the other a female, the female is incapable of producing young, but that the male may be a useful animal for breeding purposes. Many instances have occurred when the twin sister of a bull has never shown the least desire for the male. This indifference to sexual commerce arises, doubtless, from the animal's being but imperfectly developed in the organs of generation. This fact has been established by the investigations of Mr. John Hunter, who had three of these animals slaughtered for anatomical examination. The result is thus reported: "The external parts were rather smaller than is customary in the cow. The _vagina_ passed on, as in the cow, to the opening of the _urethra_, and then it began to contract into a small canal, which passed on into the division of the _uterus_ into the two horns; each horn passed along the edge of the broad ligament laterally toward the _ovaria_. "At the termination of these horns were placed both the ovaries and the testicles. Both were nearly of the same size, which was about as large as a small nutmeg. To the _ovaria_, I could not find any Fallopian tube. "To the testicles were _vasa deferentia_, but they were imperfect. The left one did not come near the testicle; the right one only came close to it, but did not terminate in the body called the _epididymis_. They were both pervious and opened into the _vagina_, near the opening of the _urethra_. "On the posterior surface of the bladder, or between the _uterus_ and the bladder, were the two bags, called _vesiculae seminales_ in the male, but much smaller than they are in the bull. The ducts opened along with the _vasa deferentia_. This animal, then, had a mixture of all the parts, but all of them were imperfect."