11. Mr Marshall on a Heifer which yielded Milk.-Edrington, by Berwick, June 16. 1830.—SIR, AS I believe the following fact, which I shall have the honour of narrating to you, to be a very uncommon one, I have from that consideration been induced to trouble you with its communication. I have two two-yearsold heifers, one of which has been observed for several months to suck the other, and evidently to draw a certain portion of milk. This circumstance rendering it necessary to separate them, curiosity suggested the trial whether the heifer which had played nurse would yield milk to the hand. On the experiment being made, she gave a full English quart of genuine milk; and on the milk being kept for thirty hours, it was covered with a coat of very good cream. The cream being churned in a bottle, afforded as much, and as good, butter, as the same quantity of any other cream would have done, under similar management. The singular part of the story is, that the heifer in question has never seen the bull. I am aware that a bitch kept up from the dog will, at the time she should have produced puppies, have milk in her dugs, but I do not know of any other female that secretes milk without being impregnated. I have the honour to be, &c. Jos. MARSHALL. To Professor Jameson.

12. Frog and Insect Plague of Mullye-As a further illustration of the nature of the atmosphere and climate in general, I shall add the following observations, which may be of some use in a medical point of view. During the rains, the vast abundance of cold-blooded animals is really astonishing. Of these, frogs are the most numerous. No place is free from this plague; every hole and every corner, both of the most retired and most public rooms, are equally infested. If a table, a chest of drawers, or a box be moved, or a carpet be lifted, they are found nestled underneath by fifteen or twenty in each corner; and thus through our halls, our bed-rooms, and our sitting rooms. There they remain during the day; and towards sunset, they begin to issue from their ambuscades, and traverse the whole house in quest of prey. The following anecdotes may give some idea of the number of insects. One morning at sunrise, I was awakened by a loud humming in my bedroom, resembling that of a market or fair held at a distance. On examination, my window was darkened, and my bed covered

with an Egyptian swarm of gigantic winged ants, about 11 inches long, and of a dark red colour, and the thickness of a crow-quill, issuing, in an uninterrupted stream, from a hole between the square tiles of the floor. Such swarms are very common, and the air is then crowded with crows and hawks that come to devour. One day, about an hour after sunset, we were alarmed from without, by what seemed an excessively heavy fall of rain pouring in torrents. On inquiry, the night was perfectly clear. Curiosity led me to go out with a light to examine the cause. I found it proceeded from an almost inconceivable number of black beetles issuing from the ground: they were somewhat larger than the first phalanx of the thumb, and their aggregated hum was the sound we had heard. To say they were coming from the earth in thousands, or tens of thousands, scarcely gives an adequate idea of their production. They must be conceived as issuing in a continued torrent from every inch over the ground, and filling the atmosphere with their flight. I shall give one other instance, which to me was peculiarly interesting, and on that account, perhaps, more observed by myself than by others. Mullye produces above all other places those insects which are destructive to books and papers. Notwithstanding the utmost care, exposure, and cleanliness, the outside of books appears perforated with small holes, as if by a pin, and apparently made for the entrance of a small species of white worms, about a quarter of an inch long; colonies of which, having thus got entrance among the leaves, there revel in destruction. They eat in serpentine labyrinths, till the whole book is traversed through and through, and destroyed. Happily they seem to have a dislike to ink, and seldom attack the printed part of the leaves till they have previously feasted on the margin. At other stations, occasional examination of the shelves, and opening the volumes, was sufficient to stop the invaders; but at Mullye, no precaution whatever had any influ ence in restraining their ravages. I may also add, that it was invariably necessary to alter the disposition of my library in the dry and rainy weather. It is no exaggeration to say that books of all kinds became, in the latter season, so swelled with moisture, that a shelf cannot then hold more than three volumes out of the four that it easily contains in the dry part of the

year; books bound with ill-seasoned, particularly with Hindoostanee, leather, and still more especially, if left to lie neglected on a table for a day or two, become covered with a stratum of white mould, at least an eighth of an inch thick; and an approach to this takes place even in the best European leather. The boards are then soaked through with moisture, whilst, in the hot winds, they are parched and rolled, as if held before a fire. Of course, all this renders their preservation extremely difficult. After this, I leave it to be imagined, that the moths among cloths, and the omnivorous white ants among almost every thing, but particularly the timber of buildings, are fully proportioned in numbers to their kindred plagues. The last thing I have to mention, though it may appear in some degree ridiculous, may yet serve to illustrate the nature of the climate. Small mushrooms grow in every corner that is the least neglected, even in the most frequented rooms: left to themselves, they would attain the height of about two inches, with a top rather larger than a shilling; but they are generally discovered and brushed away before they reach maturity. Tytler, in Trans. of Med. & Phys. Soc. of Calcutta, vol. iv.

13. Further notice of Ehrenberg's Observations on the Infusoria.-One of our late pupils, in a letter to Dr Duncan, says, "As you may well suppose, I prized highly the kindness with which Professor Ehrenberg of Berlin explained to me his diffe rent discoveries and researches. He spent nearly a whole forenoon in showing me the structure of the infusory animals; his investigations and drawings are what excited so much interest at the meeting of naturalists in Hamburgh. In these minute creatures, placed at the extremity of the animal scale, the determination of whose existence merely has hitherto formed the limit of zoological research, he has succeeded in developing a complete system of organs, by using one of Chevalier's microscopes, of 2000 powers. These animals are quite transparent; so that the whole internal structure is visible externally. They have one or more stomachs, mouth, œsophagus, intestinal canal, anus, eyes, muscular fibres, division into head and trunk. Thus far I saw distinctly; but Ehrenberg goes further; he gives to certain white striæ which are seen traversing the body of the animal, in different directions, but for the most transversely, the

denomination of blood vessels or nerves. These striæ I saw distinctly, but whether they are either vessels or nerves, I cannot tell. The motions of the animals are rapid and vigorous; and they are particularly remarkable for a large longitudinal muscle, extending nearly the whole length of the body, which enables them to bend their body into various contortions, and to alter its form in a very remarkable manner*."

14. Flying of Man and Birds.-M. Navier read to the Academy of Sciences of Paris, the report of a committee, to whom was referred the memoir of M. Chabrier, wherein is proposed a method of flying, and of directing one's flight in the air! The apparatus consists of huge wings; the cavities of which are filled with hydrogen gas, and which the flying man is to move with his arms. The report states the committee's opinion to be, not only that the apparatus proposed by M. Chabrier is incapable of effecting the object in view, but that every machine constructed upon the same principle must be equally ineffectual. To demonstrate this, M. Navier endeavours to calculate the muscular exertions made by birds in flying, in order to compare it with what man is capable of. According to his calculations, a bird, to sustain itself in the air merely, without ascending or descending, employs in a second a quantity of action equal to that which would be necessary to raise his own weight to a height of 26 feet 3 inches; but if this bird desired to move horizontally with great speed, at the rate, for example, of 49 feet 2 inches in a second, which is often the case with birds that migrate, in their annual journeys, the quantity of action which it would have to expend in a second, would be equal to that which would be required to raise its own weight to the height of 1,280 feet, or thereabouts. Thus, in this case, it would employ a force nearly fifty times greater than it required merely to sustain itself in the air. It is therefore evident, that, in order to support itself on wing, a bird must be less sensible of fatigue than a man in supporting himself on his legs, if we have respect to the quantity of fatigue which the one and the other are capable of enduring. It is

* We have before us a more detailed account of Ehrenberg's discoveries, sent from Hamburgh, but too late for insertion in the present number of the Journal.

calculated that a man who is employed 8 hours a-day in turning a crane or wheel, raises at an average rate, in every second of time, a weight equal to 15 pounds troy, 39 inches high. Supposing that the weight be 175 lb. troy, the same quantity of action is capable of raising his own weight to a height of about 33 inches; so that, cæteris paribus, it is not the ninety-second part of that which is exerted by the bird to sustain itself in the air. If the man was capable of expending, in a space of time as short as he pleased, the quantity of action which he exerts ordinarily in the course of 8 hours, it appears that he might sustain himself in the air, each day, for the space of 5 minutes.

BOTANY, HORTICULTURE, &c.

15. Erica mediterranea found native in Ireland.-Mr James Townsend Mackay, curator of the College Botanic Garden at Dublin, having made a botanical excursion to the mountainous district of Cunnemara, during the past autumn, was fortunate enough to find Erica mediterranea "growing in prodigious abundance." This is the most important addition which has of late years been made to the Irish Flora. The plant has long been cultivated in the gardens of the curious; it withstands our Scottish winters in the open border, with difficulty, and only in sheltered situations, or near the sea-shore. It was regarded as being indigenous only to the countries bordering on the Mediterranean, and to Portugal; and certainly British botanists little expected to be able to claim it as a native of the sister island.

16. Hybrid Azaleas.-Mr Gowan at Highclerc, the seat of the Earl of Caernarvon, has of late years raised many new sorts of American azaleas, by means of cross impregnation, chiefly between the high-coloured and late-flowering varieties. For mother plants, the different fine varieties of A. coccinea, were selected, major, minor, and rubescens, the anthers of which very seldom produce pollen. The two former were dusted for several successive mornings with the pollen of a late-flowering A. pontica. Many pods swelled, and produced perfect seed. The pods were gathered at the approach of winter, kept in a drawer for some weeks, and sown in the beginning of January. Of these about 400 seedlings were raised. The rubescens was impregnated with the pollen of A. calendulacea, or Lee's triumphans,