If inferior animals be subjected to absolute ether, and the influence of the vapour on their lungs, heart, and blood be carefully observed, we find that the lungs undergo a slight congestion, that the heart is filled with blood on both its sides, and the venous blood in its transit through the pulmonic circuit ceases to become arterialized. At the same time there is no destruction of the parts of the blood, and the process of coagulation is unaltered. When death is induced by pure ether, the event occurs by arrest of respiratory power. It occurs much in the same way as in death by drowning or by suffocation in carbonic acid. It is a great point to state, and it is most strictly true, that absolute ether has no directly poisonous action upon the heart. I have seen good pulsation of both sides of the heart for forty-five minutes after what may be considered the death of the animal. For this reason the action of absolute ether contrasts most favourably with chloroform. Chloroform kills by its paralyzing action upon the heart; hence when chloroform becomes deadly, it is inevitably deadly because it becomes impossible to remove it from the parts on which it acts to destroy. Ether, on its side, when it begins to cause embarrassment, is acting simply upon the respiration; and it is only necessary to cease to administer it to ensure recovery.

On the whole, after a most careful comparison of the action of absolute oxide of ethyl with the action of other volatile substances possessing anæsthetic properties, I claim for it that it is the safest of all known anæsthetics, that any indifferent effects arising, in past times, from its employment were due to badness of the article, and that science, not less than regard for human life, bids us, when a general anæsthetic is absolutely necessary, go back to ether as the safest agent.

In order to ascertain what would be the effect of actually impregnating the whole body of an animal with absolute ether, I injected one ounce of it into the aorta of an animal (a rabbit) already rendered insensible by the vapour. The result was that the fluid injected began to boil rapidly in the tissues with a free escape of ether-vapour, followed by a sudden, almost instant stiffness affecting the muscles of the whole body. This effect was due to the rapid extrication of heat from the tissues. It was a kind of general freezing of the tissues.

ACETATE OF ETHYL AND HYDROFLUORIC ETHER.

The acetate of ethyl and hydrofluoric ether are chiefly remarkable for their powerful solvent action on all the tissues of animals. They can neither of them be safely administered by inhalation, but both of them may admit of being largely and usefully employed for the destruction and removal of morbid growths. Directed on the blood they break it up absolutely, destroying alike the corpuscles, the fibrine, and the albumen. In short, hydrofluoric ether may be looked on as a universal solvent of the animal tissues; nothing escapes its action except the gelatinous structures, and these not altogether.

NITRITE OF ETHYL.

The nitrite, or more correctly the hyponitrite of ethyl, nitrous ether, is made in a similar manner to nitrite of amyl, the difference being that the nitrous fumes are passed through ordinary alcohol. The fluid when pure is of a light amber-colour; the specific gravity is 0.950, and the boiling-point 60° Fahr. The physiologist who would work with it, should mix it with absolute ether in fixed proportions-say, of ten, twenty-five, or fifty per cent. It is so volatile that without this precaution it cannot be readily employed. The action of nitrite of ethyl, as Professor Wanklyn suggested last year,

is closely analogous to the action of nitrite of amyl. Inhaled in quantities of not less than a grain, it induces the same sensation of fulness of the head, rapid action of the heart, and some suffusion of the skin. Animals subjected to it in the proportion of fifteen minims diffused as vapour through a cubic foot of air, die almost instantaneously from sudden failure of the heart, but even up to the moment of death they retain their consciousness and sensibility. The nitrite, consequently, is in no sense to be regarded as an

anaesthetic.

Precisely as the nitrite of amyl, nitrite of ethyl, when it kills, leaves the lungs entirely collapsed and so perfectly white that one could assume they had been carefully washed free of blood. This effect is due perhaps to the rapid contraction of the pulmonary capillaries. The blood is changed in. colour, the arterial blood being rendered very dark, and the venous of a deep chocolate tint; the muscles are also all left blanched, as if the death had occurred from loss of blood.

It will be remembered that, in describing the action of nitrite of amyl, I explained that in cold-blooded animals the substance suspended their animation, and that frogs that had been rendered powerless by it, and to common observation inanimate, would sometimes spontaneously recover even so long as nine days after the administration. This same phenomenon I have observed with nitrite of ethyl, together with another even more singular. It is this. If a young animal, say a kitten, be subjected so suddenly to the nitrite as to fall senseless and to appearance dead in or within the minute, it will remain in the same state for six or even ten minutes, yielding no evidence of life: it will not breathe, and the most delicate auscultation will fail to detect motion of the heart. But after a period varying from six to ten minutes it will spontaneously recommence to breathe, and with every movement of expiration a breath sufficient to dull a mirror will pass from the nostril. As the breathing recommences, the heart also begins its work, making a series of distinct intermittent strokes. This condition, looking like an actual return of life, will last so long as half an hour, and will then cease gradually, the animal lapsing again into a state of actual inertia or death.

In concluding this Report I would place the facts I have collected, in respect to the ethyl series, as follows:

1. Oxide of ethyl, or pure rectified ether as it is commonly called, is the best of all known agents for the production of general anesthesia by inhalation.

2. The peculiar difference of action between the oxide of ethyl and the nitrite of ethyl is due to the introduction of a new element, nitrogen, into the latter compound. This difference of composition makes the nitrite approach, in action, bodies of the alkaloidal class, strychnine and its analogues.

Second Report on the Structure and Classification of the Fossil
Crustacea. By HENRY WOODWARD, F.G.S.

I HAVE now to submit a Second Report upon the Fossil Crustacea, which have for some years past occupied my attention. Since the last Report made to the British Association in Birmingham in 1865, I have described and figured a new Liassic Crustacean from the Lower Lias of Charmouth-the

* The coagulation of blood is not modified.

Eger Marderi-a genus hitherto characteristic of the Solenhofen Slates of Bavaria*.

The following new genera and species of Crustacea were communicated by me to the Geological Society on the 23rd May last, and will appear in the next part of the Quarterly Journal' of that Society :

་

"2. On a new Genus of Phyllopodous Crustacea from the Moffat Shales (Lower Silurian), Dumfriesshire."

"The fossil described consists of the disk-shaped shield or carapace of an Apus-like Crustacean, the nearest known form to it being Peltocaris aptychoides, Salter, from which, however, it is at once distinguished by the absence of a dorsal furrow.

"A line of suture divides the wedge-shaped rostral portion of the shield from the rest of the carapace, the two parts being seldom found together. From its strong resemblance to Discina, the author proposed for it the generic name Discinocaris, and named the species Browniana, after Mr. D. J. Brown, who first drew his attention to it.

"3. On the Oldest known British Crab (Palainachus longipes, H.W.) from the Forest Marble of Malmesbury, Wilts.'

"The author stated that three genera and twenty-five species of Brachyurous Crustacea had already been described by Professor Reuss and H. von Meyer from the Upper White Jura of Germany; but as no limbs or abdominal segments had been met with, it was more doubtful where to place them than the species now described, which had nearly all its limbs in situ, and a portion of the abdomen united to it. Palainachus closely resembles the common Spider-crabs (the Maiada and Leptopodidae) living on our own

coasts.

"4. On the Species of the genus Eryon, Desm., from the Lias and Oolite of England and Bavaria.'

"The genus Eryon of Desmarest was established for certain extremely broad and flat forms of Astacidæ found in the Solenhofen limestone near Munich, and first described in 1757. The late Dr. Oppel has recorded fourteen species, two of which, E. Barrovensis and E. (Coleia) antiquus, are from the Lias of England. Mr. Woodward gave descriptions and figures of E. Barrovensis, M'Coy, and five other species, namely:-E. crassichelis, E. Wilmcotensis, and E. Brodiei, from the Lower Lias; E. Moorei, from the Upper Lias of Ilminster; and E. Oppeli, from the lithographic stone of Solenhofen."

The plates exhibited form (with one other) the first part of the Monograph on the Merostomata for the Palæontographical Society, and will be published shortly+.

I have lately had the opportunity to examine specimens of Limuli from the Coal-measures of Kilmaurs, Dudley, and Coalbrook-dale, and am happy to state that they have enabled me in the most satisfactory manner to demonstrate the connexion between this division of Crustacea and the older Eurypterida on the one hand and the recent King-crabs on the other. (See Report, Section D‡.)

The forms which occur in this zone (the Pennystone Ironstone) differ from Limulus in the less anchylosed condition of their segments and the possession of three well-marked divisions, representing the head, thorax, and abdomen, the latter being represented by three anchylosed segments, and having the intervening segments of the thorax free and unarticulated.

*See Geol. Mag. 1866, vol. iii. p. 10, pl. 1.
They have since (Dec. 1866) appeared.
Also Quart. Journ. Geol. Soc. vol. xxiii. p. 28.

The best example of this is the Belinurus regine of Baily, from the Irish Coal-measures; then follows the B. trilobitoides, of Buckland, the B. anthrax, Prestwich, the B. arcuatus, Baily, and lastly, the B. rotundatus of Prestwich. By placing these forms in the order indicated, we find a gradual change from the less to the more anchylosed condition of the body-segments, which attains its greatest concentration in the recent Limulus.

But besides these, we have in Hemiaspis a form more separated into distinct segments than is Belinurus regina; so that the passage from Eurypterus to Belinurus, and from that again to Limulus proper, seems capable of being bridged over, and we are justified in placing them in the same order, though separated into distinct subdivisions.

We have adopted Dr. Dana's name of MEROSTOMATA for the order, making the first suborder, EURYPTERIDA, to contain:

I characterize the order MEROSTOMATA as Crustacea having the mouth furnished with mandibles and maxillæ, the appendages to which fulfil the functions of limbs, becoming walking- or swimming-feet, and organs of prehension.

Suborder EURYPTERIDA, Huxley, 1859.-Crustacea with numerous free thoracico-abdominal segments, the first and second of which bear one or more broad lamellar appendages upon their ventral surface, the remaining segments being devoid of appendages; the anterior rings united into a carapace bearing a pair of larval eyes near the centre, and a pair of large marginal or subcentral eyes; the mouth furnished with a broad postoral plate or metastoma, and five pairs of moveable appendages, the posterior of which form great swimming-feet, the telson or terminal joint being extremely variable in form, and the integument characteristically sculptured.

XIPHOSURA (Gronov.).—Crustacea having the anterior segments welded together to form a broad convex buckler, upon the dorsal surface of which are placed two larval frontal eye-spots, and two large lateral compound eyes. Beneath this shield-like covering is placed the mouth, furnished with a small labrum and a rudimentary metastoma, and six pairs of moveable appendages. Posterior segments of the body more or less free in the fossil species, but anchylosed together in the recent species, and bearing upon their ventral surfaces a series of broad lamellar appendages. The telson or terminal segment ensiform.

I have prepared a Table which gives the species in detail, with their geological position and locality (it includes ten genera and seventy species*); also representations of all the genera save three, which require further confirmation before they can be figured otherwise than as fragments.

The geological range of this order is as follows:-We find there are 37 species in the Upper Silurian; 7 in the Lower, and 8 in the Middle Devonian; 1 in the Lower Carboniferous, and 7 in the Upper; 1 in the Permian of Russia; 1 in the Trias of Germany; 7 in the Lithographic stone of Solenhofen; 1 in the Tertiary Brown Coal of Saxony; and 4 living species inhabiting the shores of Molucca, Japan, China, the East Indies, and the eastern shores of North America. They have been met with geologically in the State of New York, especially in Buffalo county; in Ireland (Kiltorcan, fragments only); in Forfarshire, Lanarkshire, Fifeshire, and Caithness in Scotland; in Herefordshire, Worcestershire, and Staffordshire; in the islands of the Baltic (Oesel and Gothland); in Bavaria, Saxony, Poland, and as far east as the government of Perm and the Ural Mountains; so that their geological distribution is quite as wide as that of their living congeners.

The Limulus of the Upper White Jura cannot, so far as we are acquainted with it, be well separated generically from those of the present day. How vast, then, must have been the period represented between the lifetime of the Belinurus of the Coal-measures and that of the Limulus of the Oolites! and yet we should be unwilling to doubt their relationship by descent. Each antecedent period, then, must have been infinitely greater as we recede to the Wenlock, where the first traces of Pterygotus occur.

Second Report on the "Menevian Group" and the other Formations at St. David's, Pembrokeshire. By H. HICKS, and J. W. SALTER, F.G.S.

THE work of the past year has not been confined to procuring fossil specimens, although that object has been kept steadily in view.

The extent and direction of the various beds has been particularly noted; and a much greater area than was formerly suspected has been found occupied by the respective lower fossil groups Menevian, Ffestiniog, Tremadoe, and the great Arenig or Skiddaw group-formations which have only of late years been accurately explored.

Above these rocks, and forming their upper limit, we have in the St. David's promontory the Llandeilo flags, a formation that does not need a special description, since it is already well known to us in the Silurian System,' and under the name of Lower Bala in Prof. Sedgwick's works.

But

The fossil-bearing strata in the neighbourhood of St. David's are mostly exhibited in coast sections; and the grant has been very useful in enabling Dr. Hicks to employ boat-service in the work. Without boats, indeed, it would be impossible to make sure of the succession, so much have the strata been disturbed and faulted, and also in many parts covered by drift. the series, once accurately defined by this examination, could be tested by reference to roadside and brook sections, where the beds are weathered; and hence we can now offer a tolerably accurate map of all the formations, and extend it over a larger part of the district. Moreover in all about sixty-five

*This Table has since been published by the Paleontographical Society.-Dec. 1866.