ventricles. The fourth unfolds the third ventricle (ris aλan rein noia), the communication between the two latter ones, the psalloid or arch-like body (owa faidosides), fornix, and the passage from the third to the fourth ventricle. In the fifth, he gives an accurate description of the relations of the third and fourth ventricle, of the situation of the two pairs of eminences, nates, (λoura) and testes (didunia vel ogxus), the scolecoid or worm-like process, anterior and posterior, the tendons or processes, and, lastly, the linear furrow, called by Herophilus calamus scriptorius*. He appears not to have known the inferior recesses. Morgagni however concludes, from a passage of the 7th book Tig Aoyμary, that he did; but after accurately examining this and others of his anatomical writings, I cannot see any good reason for admitting the inference.

In the account of the thoracic organs, equal accuracy may be recognised. He distinguishes the pleura by the name of inclosing membrane (iμn iж(wxws, membrana succingens), and remarks its similitude in structure to that of the peritoneum, and the covering which it affords to all the organs +. The pericardium, also, he describes as a membranous sac with a circular basis corresponding to the base of the heart, and a conical apex; and after an account of the tunics of the arteries and veins, he speaks shortly of the lung, and more at length of the heart, which, however, he takes some pains to prove not to be muscular, because it is harder, its fibres are differently arranged. and its action is incessant, whereas that of muscle alternates with the state of rest. In the particular description of the parts of the organ he ascribes to the auricles a more cuticular structure than to the other parts; he gives a good account of the valves and of the vessels; and notices especially the bony ring formed in the heart of the horse, elephant, and other large animals.

The description of the abdominal organs, and of the kidneys and urinary apparatus, is still more minute, and in general very accurate. Our limits, however, do not permit us to give any abstract of them; and it is sufficient in general to say, that GaΠερι Ανατομικων Εγχειρησεων, lib. ix.

† Αλλ' ὁ ὑπεζωκος οὕτως ὑποτείνεται πασι τοις ενδον του θωρακος οργανοις ὡς ὁ περιτοναίος ελέχθη,και εδείχθη τοις κατω των φρένων. Ibid,

OCTOBER-DECEMBER 1829.

L

len gives correct views of the structure and distribution of the peritoneum and omentum, and distinguishes accurately the several divisions of the alimentary canal, and the internal struc ture of its component tissues. In the liver, which he allows to receive an envelope from the peritoneum, he admits, in imitation of Erasistratus, a proper substance or parenchyma, interposed between the vessels, and capable of removal by suitable dissection.

His description of the organs of generation is rather brief, and is, like most of his anatomical sketches, too much blended with physiological dogmas.

This short sketch may communicate some idea of the condition of anatomical knowledge in the days of Galen, who indeed is justly entitled to the character of rectifying and digesting, if not of creating, the science of anatomy among the ancients. Though evidently confined, perhaps entirely, by the circumstances of the times, to the dissection of brute animals, so indefatigable and judicious was he in the mode of acquiring knowledge, that many of his names and distinctions are still retained with advantage in the writings of the moderns. Galen was a practical anatomist, and not only describes the organs of the animal body from actual dissection, but gives ample instructions for the proper mode of exposition. His language is in general clear, his style as correct as in most of the authors of the same period, and his manner is animated. He appears to have been the first anatomist who can be said, on authentic grounds, to have attempted to discover the uses of organs by vivisection and experiments on living animals. In this manner, he determined the position, and demonstrated the action, of the heart; and he mentions two instances in which, in consequence of disease or injury, he had an opportunity of observing the motions of this or gan in the human body. In short, without eulogizing an ancient author at the expense of critical justice, or commending his anatomical descriptions as superior to those of the moderns, it must be admitted that the anatomical writings of the physician of Pergamus form a remarkable era in the history of the science; and that, by diligence in dissection, and accuracy in description, he gave it a degree of stability and precision which it has retained through the lapse of many centuries.

(To be continued.)

On the occurrence of Chalk-flints in Banffshire. By JAMES CHRISTIE, Esq. Secretary to the Banff Institution. Com

municated by the Author *. .

SOME time ago I took the liberty of submitting for your inspection specimens of a quantity of flints found scattered and mixed with the water-worn stones and shingle along the shore of Boyndie Bay †, to the westward of Banff, and to state, that flints of a similar description are occasionally found to the eastward as far as Peterhead. I had not seen any organic remains in the flints of this part of Scotland, to enable me to form an opinion as to their being of the chalk-formation ‡. Since that time, I have met with abundance of flints on the hill or rising ground between Turiff and Delgaty Castle. The surface of the ground there is irregular, rising occasionally into hillocks, and sinking into hollows, filled with bogs and swamps. These hillocks are composed of a conglomerate or pebbly mass, having a base or ground of white or grey colour, and apparently composed of decayed felspar, and very minute scales of mica or talc, or both, in which are imbedded rounded pebbles of greyish-white translucent quartz-rock. The quartz-pebbles are from the size of a pea to that of a hen's egg. This conglomerated mass is here and there alternated with or traversed by a white quartzy sand, with scales of mica. The whole conglomerated mass is mixed up with flints, of various sizes and forms. The flints are yellow,

At p. 381. of last volume of this Journal, we noticed Mr Christie's discovery of flints on the shore near Banff.-EDIT.

+ The flints sent me from Boyndie Bay, are of the same description with those found near Delgaty. They contain traces of zoophytic organic remains. EDIT.

Some years ago, while examining the geognosy of the vicinity of Peterhead, our attention was directed to the chalk-flints found in that neighbourhood, by previous information. We traced them extending over several miles of country, and frequently imbedded in a reddish clay, resting on the granite of the district. These flints contain sponges, alcyonia, echini, and other fossils of the chalk-flint, thus proving them to belong to the chalk formation, which itself will probably be found in some of the hollows in this part of Scotland.-EDIT.

brown, and grey, more or less translucent, often enveloped in a white siliceous opaque crust, and containing organic remains principally of sponges or alcyonia. In some flints the centre is hollow, and the walls of the cavity lined with calcedony. One of the hillocks has been opened to the depth of about fifteen or eighteen feet. The quartz-pebbles become more translucent the deeper the pit is opened; and the flints, which, at the surface of the ground, are generally of a brown colour, exhibit other tints in the interior of the bed. The hollows between the hillocks are destitute of pebbles and gravel, and have a clayey bottom. The direction of the hollows appears in general to run east and west. These hollows may perhaps have been scooped out, and the beds containing flints and pebbles of quartz carried off by some of those mighty inundations which have more than once swept over the face of nature.

As to the extent of the deposite, I can say but little in one direction, I have traced it for nearly a mile, occasionally interrupted by the hollows. The point where the specimens were taken up, is about half a mile distant from another patch, through which the ditch I formerly mentioned has been cast. At that point, also, the flints and quartz-pebbles, and other deposites, are the same as those already mentioned. The spot where these deposites are found is in the interior of the country, about ten miles from the sea, and is the highest ground in the neighbourhood. I have not been able to ascertain the depth of the bed, as the pit filled with water on digging down, and the water became thick with the clayey or chalky matter. The workmen, however, told me, that farther down the hill they had met with a bed of white clay, and they believed the deposite of pebbles, flints, &c. rested on it.

I have never seen the chalk formation, but, as I understand it, this deposite has many features of its upper strata. The flints are abundant throughout the whole, and I found them on the surface at a mile distant from the hillock where the specimens were taken from

* We trust Mr Christie, and other members of the Banff Institution, will continue their researches in regard to these flints, for possibly the chalkformation itself may be found in situ in this part of Scotland.-EDIT.

Aerial Shadows seen from the Cairngorm Mountains. By JOHN MACPHERSON GRANT, Esq. jun. of Ballindalloch. In a Letter to the Editor.

As

s you expressed a wish to have some account, in writing, of the atmospheric appearance seen by Sir Thomas Dick Lauder and myself, in our late ramble among the Cairngorms, I have transcribed the following passage from my note-book, and attempted to give, by the accompanying diagram, some idea of the beautiful phenomenon which we witnessed *.

"On the 10th October 1830, at 3 P. M. we reached the summit of Ben-mac-dhuie. A thick mist enveloped the mountain, like a curtain, concealing from view the whole of the surrounding range of the Cairngorms, with the exception of the giant hill on which we stood, and the scarce less elevated tops of Cairentoul and Bræriach. The upper bounding line of the mist was so perfectly horizontal, and the apparent undulations on its surface resembled so closely the waves of the sea, that it was extremely difficult to divest one's-self of the idea that we stood on some desert rock in a vast ocean, with two others of similar character in sight. The day was fine; and the sun, though fast declining to the west, shone so bright and powerfully on the huge masses of granite around us, that we sat down for more than half an hour to rest from our fatigues, and to prolong, as far as might be, the satisfaction of being on the highest ground in Britain.

"On descending from the top, at about half past three P. M., an interesting optical appearance presented itself to our view. We had turned towards the east, and the sun shone on our backs, when we saw a very bright rainbow described on the mist before us. The bow, of beautifully distinct prismatic colours, formed about two-thirds of a circle, the extremities of which appeared to rest on the lower portion of the mountain. In the centre of this incomplete circle, there was described a luminous disc, surrounded by the prismatic colours displayed in concentric rings. On the disc itself, each of the party (three in number), as they stood at about fifty yards apart, saw his own figure most distinctly delineated, although those of the other two

* The diagram will be given in next Number of Journal, having been received too late for the present.