of the motor nerves. In frogs under its operation the terminal branches of these nerves within the muscles lose their excitability in a few minutes, whilst their trunks become affected an hour or two later. If, after the nervous extremities have become paralysed, the heart of the animal be excised so as to prevent the nerves from receiving any further share of the poison, the nervous trunks may retain their excitability for three or four hours.

4. The brain is less affected by the urari than the nerves in the muscles; still when, by ligature of the two aortic arches, in frogs, the poisoning is confined to the anterior half of the body, the voluntary movements of the limbs speedily cease, whilst automatic movements, of doubtful nature and probably proceeding from the medulla oblongata, may be still observed for half an hour or an hour after the poison has begun to operate.

5. The spinal cord is considerably less affected than the brain by this poison, and by local limitation of the poisoning (as in No. 4), it is found that the cord retains its reflex activity from half an hour to an hour and a half, and the excitability of its white substance or its conducting power from two to three hours after the poison has taken effect. It is worthy of remark that in such cases the impaired reflex activity of the spinal cord may be revived by strychnia directly applied to it.

6. The sensory nerves, as shown also by locally limited poisoning, retain their functional activity as long at any rate as reflex actions can be excited, and when the depressed reflex activity has been revived by means of strychnia, these nerves are found not to have been in the slightest degree injured, so that it seems doubtful whether the urari in any way affects them.

7. The nerves of the involuntary muscles and of the glands are also paralysed by the action of urari, at least I find this to be true in the following cases, viz.—

iris.

a. The pneumogastric, as regards its influence on the heart.

b. The sympathetic (its cervical portion), in its relation to the

c. The nerves of the posterior lymph-hearts of the frog.

d. The nerves of the vessels in the web of the frog's foot.

e. The splanchnic nerves of the rabbit, as affecting the peristaltic

motions.

f. The nerves governing the secretion of the submaxillary gland in dogs.

In

8. The voluntary muscles remain perfectly excitable, but show a greater tendency than usual to merely local contractions. general the cadaveric rigidity of these muscles appears to set in later than usual.

9. The plain or non-striated muscles also remain long irritable after poisoning by urari.

10. The heart, in amphibia, is little affected by urari. Its pulsation as well as the circulation of the blood goes on regularly for many hours after the poisoning is established. The only thing worthy of note is that the beat of the heart appears to be somewhat quickened, probably from paralysis of the pneumogastric nerves. In frogs poisoned with urari, the heart, when cut in two, shows the usual phenomenon, namely, that the half which contains the ganglia continues to pulsate whilst the other does not; from which it may be inferred that these ganglia are not paralysed. As to the nerves in the substance of the heart, those at least which are derived from the pneumogastric are unquestionably paralysed (vide No. 7).

11. The lymph-hearts of frogs poisoned with urari soon cease to

move.

12. The blood of animals poisoned by urari is fluid and dark, but coagulates when drawn from the vessels, and forms a weak clot which is but little reddened by exposure to air. Directly mixed with blood, urari does not prevent coagulation, but the blood in this case also remains dark and scarcely reddens on exposure.

13. The blood of animals poisoned by urari has the same poisonous qualities as that substance itself, but not in a degree sufficient to produce the full effects of the poison. Urari when directly mixed with blood loses none of its efficacy.

14. Urari, in concentrated solution, applied locally to nerves extinguishes their excitability, but only after a considerable time, and it appears to act similarly on the nerves in the substance of the muscles. Dilute solutions have no injurious operation. Applied directly to the brain and spinal cord, urari is altogether harmless provided its absorption be prevented.

15. When artificial respiration is kept up in quadrupeds poisoned with urari, I find that, as observed by Bernard, many of the secre

tions become increased-as the tears, saliva, urine and mucus of the air-passages, which effect appears to be owing to the paralysis of the vascular nerves and consequent dilatation of the vessels caused by the poison.

16. In mammalia urari causes death by paralysis of the respiratory nerves and suppression of the respiration, which brings on convulsions in these animals as a collateral effect. In frogs the final extinction of the functions may also be partly ascribed to suppressed action of the lungs and defective oxidation of the blood, which at length renders the heart unfit to perform its office; but it must be observed that in this case the cause of death is not so plain, inasmuch as in these animals the functions are in a great degree independent of the pulmonary respiration.

II. STRYCHNIA.

Some experiments with strychnia (the acetate) gave the following results:

1. Strychnia has not the least influence on the peripheral nerves through the blood, which is best shown by cutting the nerves before administering the poison.

2. Strychnia paralyses the motor nerves of the voluntary muscles by exciting them to too energetic action, a paralysis which may be compared to that caused by powerful electric currents acting upon the nerves. In frogs, when the tetanic spasms are over, the nerves often show no trace of excitability; in mammalia they generally retain it in a slight degree, but never show the same energy of action as when uninjured.

3. Strychnia does not affect the sensory nerves.

4. The heart is not affected by strychnia, not even during the tetanic spasms, with the exception only that its pulsations are sometimes a little slower during the tetanic state. On the contrary, the lymph-hearts of frogs contract themselves as soon as the tetanus begins, and remain in this state as long as the spasms last.

5. The tetanic fits can be brought on in two ways; first, through the sensory nerves, which, by irritating the grey substance of the spinal cord, produce the tetanic contractions as reflex movements; and, secondly, through the brain, which is not affected at all by strychnia and preserves its powers of volition and sensation. Accord

ingly, animals poisoned with strychnia try to move in the ordinary way, but every attempt brings on a tetanic fit, so that it is plain that the spinal cord may also be excited by the brain to its peculiar actions.

6. If the tetanus produced by strychnia has been strong, the muscles are less irritable and pass much sooner into the state of cadaveric rigidity, which is very strongly marked, and seems to last longer than it generally does. The same early onset of rigidity may be observed in animals killed by tetanus excited by electricity.

X. "Researches on the Foraminifera."-Part II. By WILLIAM B. CARPENTER, M.D., F.R.S., F.G.S. &c. Received June 19, 1856.

(Abstract.)

In the pursuance of his plan of minutely examining certain typical forms of Foraminifera, for the purpose of elucidating their history as living beings, and of determining the value of the characters they present to the systematist, the author in this memoir details the results of his investigations on the genera Orbiculina, Alveolina, Cycloclypeus, and Heterostegina.

The genus Orbiculina has long been known, through its prevalence in the West Indian seas, which causes its shells to abound in the shore-sands of many of the islands of that region. These shells present great varieties of form, and have been ranked under three distinct species; but M. d'Orbigny has correctly inferred, from a comparison of a large number of specimens, that their diversities of form are partly attributable to differences in the stage of growth, and partly to individual variation, so that all the Orbiculina of Cuba, the Antilles, &c., are referable to but one specific type. Of the essential features of its structure, however, he would seem to be quite ignorant; since he ranges Orbiculina in a distinct order from Orbitolites, to which it is very closely allied. This alliance was first pointed out by Prof. Williamson, whose account of the structure of Orbiculina, though defective and erroneous in certain points, is nevertheless correct in the main.

The author has had the opportunity of examining not merely a

considerable number of West Indian specimens, but also a set of specimens peculiarly remarkable for their high development, which form part of Mr. Cuming's Philippine collection. Many of these present the form of flattened disks, marked with concentric circles, and having one or more rows of pores at their edges, not distinguishable, save by their prominent central nuclei, from certain forms of Orbitolites formerly described. The similarity is equally great in their internal structure; so that, if a marginal fragment only were submitted to examination, it would not be possible to say with certainty whether it belonged to an Orbitolites or an Orbiculina. The distinguishing character of the latter is derived from its early mode of growth, which is uniformly spiral; and from the circumstance that each of the first three or four turns of the spire not merely surrounds, but invests its predecessor, thereby producing an excess in the thickness of the earlier over that of the later-formed portion, which gives rise to the central protuberance already mentioned. The transition from the spiral to the cyclical mode of increase is effected (just as it is in those individuals of Orbitolites which begin life upon the spiral type) by the opening-out of the mouth of the spire, which extends itself on either side around the previously-formed body, until its two divisions meet on the opposite side, where they coalesce so as to constitute a complete annulus. This transition may take place at any period of growth after the completion of the first four or five turns of the spire; so that we sometimes meet with small specimens which have already become discoidal and taken-on the cyclical plan of growth, whilst we occasionally meet with full-grown specimens which retain the spiral form, and show no tendency whatever towards the assumption of the cyclical plan of growth. These facts obviously point to the very subordinate value of plan of growth as a distinctive character.

The author next proceeds to a like investigation of the genus Alveolina, which he shows to bear a very marked resemblance to Orbitolites and Orbiculina, in the simple concretionary texture of the shell, in the freedom of communication everywhere existing among the chambers, in the mutual relations of these to each other, and in their mode of communication with the exterior; whilst its plan of growth is very different, the axis round which the spiral turns being greatly elongated, and every additional whorl of the spire pro