To contrive a cypher which shall be at once secure from detection, and easy in its application, has been considered a problem of some difficulty; and if we may judge from the failure of several very well contrived attempts, such a cypher is still a desideratum: One of considerable difficulty was proposed in Dr. Rees's new Cyclopædia; but this has been decyphered by Mr. Gage, Another cypher, contrived with great ingenuity, was proposed by Professor Herman about the year 1750. It was offered with great confidence as a challenge for the learned of Europe. It was, however, decyphered a few years after by M. Bequelin, who read a memoir on the subject to the Academy of Sciences of Berlin, which was pub lished in their Transactions for the year 1758. This paper contains an explanation of the law of the cypher, and is perhaps the most elegant specimen of reasoning on this subject which has yet appeared. It might well be selected as a model for all future inquiries of a similar nature. The two cyphers just alluded to are perhaps amongst the most difficult that have been contrived; but notwithstanding their failure, I will venture to propose the annexed as a specimen of a cypher which possesses very considerable advantages over either of them. In point of simplicity it yields to none; for each character represents a letter; consequently the number of characters to be written does not exceed the number of letters. In the former of the two cyphers just mentioned each letter is represented by two characters; and in the latter one letter is sometimes denoted by the combination of three characters. In point of security, the cypher which I propose will, I imagine, be found unexceptionable. It is constructed purposely with a view to defeat all the rules of decyphering; and though the translation of this specimen were to be given, yet I am convinced the cypher would remain secure. With respect to the number of varieties of which this cypher admits, it is unlimited; and the key itself may be changed with equal facility at every line or at every letter. Combining such advantages, it might be imagined that this cypher is encumbered with laws which would render it too tedious for practice. This, however, is by no means the case. When the key is known, it is easy to interpret it; and such is its simplicity, that no written memorandum of the key need be preserved; for it may be written out at any time without scarcely the least effort of the memory.

C. B.

VOL. VII. N° II.

H

Account of the Worm with which the Stickleback is infested.
By Thomas Lauder Dick, Esq. With a Figure.

SIR,

Relugas, near Forres, N. B. Nov. 17, 1815. GMELIN, in his description of the gasterosteus aculeatus, or three spined stickleback (Syst. Nat. p. 1323), says of that fish "vermibus intestinalibus tanto crebrius infestatus." And Mr. Donovan, in his splendid work on British fishes also remarks with regard to this gasterosteus that "Frisch, Pallas, and M. Fabricius, who have entered into their history, observe that it is greatly tormented with worms at certain seasons, a fact sufficiently obvious to every common observer." Although this circumstance in the natural history of these fishes appears thus to be already generally well understood,. yet the following particulars, which I now presume to offer you, may not perhaps be altogether unacceptable.

Early in the month of June last my neighbour and friend Mr. Brodie, of Brodie (a Gentleman well known as a naturalist), had about 50 or 60 of the three spined sticklebacks brought to him alive in a vessel of water from one of his ponds. Most of these

little fish presented the ordinary appearance; but many of them were of a form so very singular as to induce me almost to hesitate in pronouncing, at first sight, whether they were the same animal or not. Supposing the head and shoulders to have been removed,

1

te

Engraved for D.Thomson's Annals. for Baldwin, Cradock & Joy, Paternoster Row. Feb'1.1816.

the shape of the remainder of the fish bore a strong resemblance to that of a fiddle, the tail of the gasterosteus answering to the fingerboard and head of the instrument. But the sketch (Plate XLIII. Fig. 1) will afford the best idea of their figure, as seen by looking down upon them from above when swimming about in the vessel which contained them. In order to ascertain the cause of their extraordinary malconformation, several of them were subjected to immediate dissection, when from three to, in some cases, seven or eight white worms, the tænia solida of Gmelin (vid. p. 3079), were found in each individual. Neither roe nor milt could be discovered in any of these diseased sticklebacks; though in the others brought in at the same time, which were healthy and properly shaped, and which upon dissection were found free from tæniæ, either the lactes or ovarium in complete perfection was invariably found. In order to submit them to further observation, and for the purpose of watching how the disease would terminate, three of the fiddle-shaped sticklebacks were preserved alive in a soup-plate full of water, which was carefully changed every morning. These fish were regularly supplied with a number of live red worms.from the same pond, about six or seven-eighths of an inch in length: these were the nais digitata of Gmelin (vid. p. 3121), of which each of them ate three or four every day. All this time they were perfectly lively and active, and were frequently observed fighting with each othe for the small worms on which they fed. About a fortnight after they were put into the plate, one of them by some accident sprung out of it, and in the morning was found dead near it on the frame on which it stood. Upon its being dissected, two tæniæ were discovered in it. The two sticklebacks which remained continued in their usual state of activity until about the middle of October, when one of them began to appear indolent and feeble, and at last, towards the end of the same month, was one morning found dead, and four tæniæ of the length of from an inch and an half to rather more than two inches, which had been discharged from its body, were observed in the plate near it. The third gasterosteus now began to show symptoms of divining, and on the morning of the 7th of the present month (Nov.) it died in the same way as the last had done. Having all along taken much interest in the fate of these fish, Mr. Brodie, to whom I had accidentally promised a visit on that day, ordered the plate and its contents to be preserved as it was until I should see it. On examining the dead stickleback, which was about an inch and an half in length, I observed small globular pustules on one or two different parts of its body. Three tænia. were lying in the plate beside it, and the aperture of the anus was so much enlarged and lacerated as to leave no doubt that the worms had forced their way out at that place. The tænia were above two inches in length by about the fourth of an inch in breadth, perfectly white, flat, and formed, like other tape-worms, of a number of rings. Their shape was smaller towards the head; but the other extremity terminated more bluntly, being of the same