236 Miscellaneous, 



broken off by the carpenter in his endeavours to extract it from the 

 position in which it was tightly wedged, and the point, with some 

 inches of the horn, still remains in the shij:). It was splintered by 

 the same cause, and is glued together in the state in which you will 

 receive it. 



" It is remarkable that it entered the vessel, not, as one would sup- 

 pose, in a horizontal direction, but nearly vertically, passing rather 

 obliquely through two of the floor timbers within a few feet of the 

 keel. 



" Believe me to be yours sincerely, 



" Robert M'Calmont." 

 " To William Thompson, Esq., Belfast." 



The following paragraph which appeared in the Caledonian Mer- 

 cury in October 1843 may be added : — 



" Extraordinary Circumstance. — The brig Lord Byron-, of Lime- 

 kilns, when on her voyage, at the end of last month, from the West 

 Indies to Liverpool, suddenly s])rung a leak, without any apparent 

 cause. It was considered advisable to return to Jamaica, and, on the 

 cargo being taken out and the vessel examined, it was found that the 

 damage was occasioned by a sword-fish. The sword or bill of the fish 

 had passed through the copper sheathing, then through the planking, 

 in a slanting direction, to the extent of five inches, and also about 

 eight or ten inches into the dead wood of the keel ; leaving an open- 

 ing in the planking in each side sufiicient to admit the hand of a boy. 

 A piece of the sword retained by the Captain is six inches long and 

 one and a half inch thick, of solid bone ; but a longer j^iece remains 

 in the keel. The strength of the sword-fish must be very great, and 

 it may have been the cause of the loss of several vessels. The vessel 

 referred to was carried into port with very great difficulty." 



Donegal Square, Belfast, Jan. 31, 1841. Wm. Thompson. 



UPON THE SECRETION OF SILK. 



The question has lately arisen, contrary to the old opinion of the 

 silk (especially that of the silkworm) being contained in a fluid state 

 within the reservoirs, whether it does not exist there already formed 

 into a thread, and the cater})illar have merely to unwind a skein of it 

 in constructing its cocoon. Straus-Durckheim expresses at some 

 length (p. 88. vol. ii. of his recent work upon Comp. Anat.) his con- 

 viction that such is the case, both from anatomical observation and 

 experiment, but the researches of M. Robinet have led him to the 

 following difl^erent conclusions : — 



1 . The silk escapes by a simple membranous orifice, situated in a 

 conical and fleshy appendage adhering to the labium of the silkworm. 



2. The silk reaches this orifice by a single very short canal result- 

 ing from the union of the two serigenous csecal tubes. 



3. The anterior part of these tubes is capillary; the middle is 

 very much swollen, and constitutes the reservoir properly so called ; 

 the posterior part consists of a very long slender cylinder, which is 

 probably the secreting organ. 



