Queries and Answet'S. 765 



Art. II. Queries and Anstoers, 



In twin-born Calves, both areso7)ietimes fertile. — Sir, In answer 

 to the query of U. of Cambridge (p. 396, 397.), " In twin-born 

 calves, is one of the two invariably sterile ? And, if the two 

 be male and female, is the sterile one invariably the female?" 

 I beg to state that the female is not invariably sterile, although 

 such an idea is very prevalent. Joseph Holroyd, Esq., of 

 Withers, near Leeds, told me, in July, 1826, when we were 

 conversing upon this subject, that he had a cow which calved 

 twins, a bull calf and a cow calf. As popular opinion was 

 against the cow calf breeding, it being considered a free 

 martin, as described by John Hunter, Mr. Holroyd was 

 determined to make an experiment of them, and reared them 

 together. They copulated, and in due time the heifer brought 

 forth a bull calf, and she regularly had calves for six or seven 

 years afterwards. 



I would refer your correspondent to John Hunter's Ob- 

 servations on certain Parts of the Animal (Economy, 4to, 2d 

 edition, p. ob., where he will find his paper on the free mar- 

 tin, originally published, I believe, in the Philosophical Trans- 

 actions ; and at p. 60. of the same paper, J. Hunter candidly 

 states : — " Although what I have advanced with respect to the 

 production of free martins be in general true, yet, by the 

 assistance of Benj. Wray, Esq., of Denham, near Uxbridge, 

 who knew my anxiety to ascertain this point, I was lately fur- 

 nished with an instance which proves that it does not invaj^i- 

 ably hold good,^^ He then goes on to state the case, and the 

 dissection of the animal: — " 1 have heard of other twin cows 

 breeding ; but as I cannot call to mind the names of the indi- 

 viduals who communicated the circumstances to me, I have 

 only mentioned one of undoubted authority. Yours, &c. — 

 Richard Moulson, M.D. Halifax, Yorkshire, May 30. 1832. 



Moles do swim of choice, (p. 78. 296.) — J. D., at p. 78. 

 296., asks if moles swim of choice ? I answer, yes. Last 

 summer and autumn I visited a river at the bottom of the 

 Botanic Garden, several times very early in the morning and 

 late in the evening, for the purpose of procuring a specimen 

 to preserve of the kingfisher (^Icedo I'spida L.), which is fre- 

 quently to be met with here. One morning as I sat very 

 quietly, I observed a mole come out of an osier holt, and run 

 across a grass path and take to the water ; when it was about 

 half across the river, I ran to the edge of the water, and the 

 mole then made a perceptible attempt to dive, but merely 

 immersed his nose in the water for half a minute, and rapidly 

 gained the shore, and soon disappeared in a hole of the bank. 



