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ordinarily occupied by a series of tabulæ or vesicular endotheca, and the endotheca often occupies the greater part of the corallum. The septal lamina, although generally very incomplete, are never perforated or 'poutrellaire;' finally, their lateral faces are not furnished with synapticulæ, and are only rarely granular.

“ The individual corallites increase by gemmation, and never by fissiparity. The buds are generally calicular, and this form of gemmation may continue in the same individual. In some cases the gemmation is lateral.” The originators of the “Rugosa” divide them into four families :1. Stauridæ.

3. Cyathophyllidæ. 2. Cyathoxonidæ.

4. Cystiphyllidæ. In criticising this classification some definite plan must be adopted, which should refer to the philosophy of the classification of the Aporosa and Perforata. In fact the scheme of generic subdivision and differentiation adopted in the Neozoic corals can be made to apply to those of the Palæozoic age. Thus an essential distinction is made amongst the Neozoic corals by the simple or compound nature of the corallum. Simple Caryophyllinæ constitute a series of genera, and the compound forms are separated as Cænocyathi. Now in the Palæozoic genus Cyathophyllum, MM. Milne-Edwards and Jules Haime admit, in direct opposition to the Neozoic scheme, both simple and compound forms. This, I think, is an error, but only an error of classification, for there can be no reasonable doubt of the intimate gencalogical relation of the simple and compound genera of Cyathophyllum.

Families *. 1. STAURIDÆ.—Genera: Stauria, Holocystis, Polycælia, Metriophyllum, Conosmilia.

Of these Holocystis is a Lower Greensand form, and Conosmilia is Australian and Tertiary.

MM. Milne-Edwards and Jules Haime place the Stauridæ first in their list of families; but it would have made the classification more simple if the second family took their place; and I propose to change the order of arrangement, but proceed at present in the recognized method.

There is a well-developed wall in the Stauridæ ; the septa are continuous from the top to the bottom of the calice, and are eminently quaternary in their arrangement. The endotheca assumes the vesicular structure between the septa, and then crosses over in the form of horizontal tabulæ. The Stauridæ approach the Cyathophyllidæ more than the Cyathoxonidæ; and, indeed, the only essential distinction between the first two families is in the truly lamellar state of the septa in the first instance, and in the incomplete condition of them in the second. Nevertheless it should constitute a family distinction.

Two of the Stauridian genera are compound, and three are simple forms.

Stauria, which as yet has not been found in British strata, has neither columella nor costæ, whilst Holocystis has both of these structures. There is no reason why the last-named genus should not be the lineal descendant of tho former. Both were probably shallow-water forms in the neighbourhood of reefs.

The simple forms Conosmilia and Polycælia are closely allied, and the presence of the first in the Australian Tertiaries, and of the other in the Euro

* See Hist. Nat. des Coralliaires, rol. iii. p. 325 et seq. (Milne-Edwards and Jules Haime).

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pean Permian, is highly suggestive. The remaining form, Metriophyllum, offers a great difficulty, for if the received classification be adopted, the genus is very aberrant. Thus Metriophyllum has not four principal septa, but the septa are arranged in four groups, a gap or kind of septal fossula being between each group. The British Devonian species (M. Battersbyi, Ed. & H.) was founded upon a transverse section of a slab, and therefore the entiro nature of the septa could hardly be determined. The question arises at once, what do those septal fossulæ mean? And another follows very naturally, aro they in relation with the primary septa ?

I think that they denoto a difference in the physiology of the polype, for they would permit of a deeper development of the visceral cavity and an enlarged condition of the ovarian apparatus. Moreover, these fossulæ may have much to do with the growth of the coral in calibre and in septal number; and, furthermore, Lindström's admirably suggestive paper on the operculated structures, necessitates much attention being paid to them. Can there be any genealogical classification which will connect in one family such different forms as Metriophyllum and Polycoelia? I think not.

Eliminating, then, Metriophyllum from the Stauridæ, I propose to permit the genus to remain per se for the present.

2. CYATHOXONIDE.—Genera: Cyathoxonia, Palæozoic; Haplophyllia(Pourtales) and Guynia (Duncan), recent.

This group has no endotheca, and resembles the Turbinolidæ amongst the Neozoic corals, but it has the quaternary arrangement of the septa.

All the forms are simple. Cyathoxonia preceded the others, and all are closely allied. The foreshadowing of the Neozoic forms in the Palæozoic Cyathoxonidæ is evident enough.

Report on the Heat generated in the Blood during the process of

Arterialization. By ARTHUR GAMGEE, M.D., F.R.S.E., Lecturer on

Physiology in the Extra-Academical Medical School of Edinburgh. In a Report which was submitted to the British Association in Liverpool last year*, I very shortly alluded to the objects which I had in view in commencing an investigation on the very obscure subject of the heat generated during the arterialization of blood.

I pointed out that two methods of research suggested themselves as likely to elicit facts which would lead to a solution of the problem, and I stated that both these methods had been employed by previous observers.

The first method, which would at first sight appear likely to furnish us with most important data, consists in ascertaining the temperature of the blood in the right and left ventricles of the heart of living animals. If our methods of experimenting were free from the great fallacies which are introduced when we are compelled to interfere, in a serious manner, with the central organ of the circulation, and if it resulted that the left side of the heart contained blood warmer than that of the right side, we should be driven to the conclusion either that during the process of absorption and combination of the oxygen of the air a very perceptible evolution of heat had oc

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* Report of the Liverpool Meeting, p. 228.

curred, or that within the pulmonary vessels considerable oxidation processes of the blood contained in them had taken place. If, on the other hand, the temperature of the left side were the same as that of the right side, or lower, the question would still remain an open one ; for heat might be evolved in the lungs, and yet the quantity might be insufficient to counterbalance the loss of heat due to the evolution of large quantities of watery vapour, of carbonic acid, and to the heating of the air which we daily inspire.

The first method, or that which consists in ascertaining the temperature of the two sides of the heart, need scarcely be touched upon at present; and I shall merely confine myself to the statement that, in the hands of the most experienced and reliable physiologists, and specially in those of Professor Claude Bernard, it has led to the curious result that the blood which reaches the left ventricle is colder than that which leaves the right. This result would, at first sight, appear to prove that if any heat be evolved in the lungs, its amount is not sufficient to compensate the losses to which I have already alluded, and rendered it absolutely essential that fresh experiments should be conducted by a second method, which consists in ascertaining whether, when venous blood removed from the body is agitated with oxygen or atmospheric air, any changes occur in its temperature.

The first step in the inquiry consisted in ascertaining the specific heat of blood, for none of the experiments previously made had led to trustworthy results. Dr. Crawford had, in the last century, advanced a theory of animal heat which was based upon an assumed difference in the specific heat of arterial and venous blood: he supposed that the former possessed a very high, and the latter a comparatively low specific heat; so that in becoming arterialized in the lungs, the heat resulting from the condensation, solution, and probable chemical combination of oxygen with the blood became latent, being, however, evolved as the blood circulated through the body, when, becoming venous, it acquired a continually diminishing specific heat. Dr. John Davy, in his Researches, Physiological and Anatomical,' vol. i. p. 141, in a chapter entitled “On the Capacities of Venous and Arterial Blood for Heat," described experiments which contradicted the hypothesis of Crawford as to the difference in the specific heat of the two varieties of blood, although the extraordinary discrepancies between different experiments rendered it impossible that any calculations could be based upon Dr. Davy's results. In his experiments, Dr. Davy made use of defibrinated blood, employing for the determination of specific heat the methods of mixture and rate of cooling.

In the experiments which I performed last year, and which are published in the last volume of the Reports of the British Association, I made use of the method of mixture, taking care to adopt all the precautions which modern experience has suggested. Making use of the perfectly fresh blood of the ox, which was sometimes venous, sometimes arterial, I obtained remarkably concordant results, the mean of which gave 1:02 as the coefficient of the specific heat of blood. Having made this determination, I could pass to the experiments intended to determine whether, in being arterialized, blood which is perfectly venous becomes hotter.

As a preface to my own researches on this subject, it is incumbent upon me to allude to all the observations which have been made on this subject. In the second volume of Dr. Davy's Researches, Physiological and Anatomical,' at p. 168 a section is devoted to the following question:-“When oxygen is absorbed by the blood, is there any production of heat?

“ To endeavour to determine this point,” says Dr. Davy, “ of so much interest in connexion with the theory of animal heat, a very thin vial, of the

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capacity of eight liquid ounces, was selected and carefully enveloped in bad conducting substances, viz. several folds of flannel, of fine oiled paper, and of oiled cloth. Thus prepared, and a perforated cork being provided holding a delicate thermometer, 2 cubic inches of mercury were introduced, and immediately after it was filled with venous blood kept liquid as before described. The vial was now corked and shaken ; the thermometer included was stationary at 45°. After five minutes that it was so stationary the thermometer was withdrawn; the vial, closed by another cork, was transferred to a mercurial bath, and 14 cubic inch of oxygen was introduced. The common cork was returned, and the vial was well agitated for about a minute: the thermometer was now introduced; it rose immediately to 46°, and, continuing the agitation, it rose further to 46°.5, very nearly to 47o. This experiment was made on the 12th of February, 1838, on the blood of the sheep. On the following day a similar experiment was made on the venous blood of man, The vial was filled with 11 cubic inches of this blood, its fibrine broken up in the usual manner, and with 3 cubic inches of mercury; the temperature of the blood and mercury was 420.5, and the temperature was the same after the introduction of 3 cubic inches of oxygen. The temperature of the room being 47°, a fire having shortly before been lit, the vial was taken to an adjoining passage, where the temperature of the air was 39o. Here the vial was well agitated, held in the hand with thick gloves on as an additional protection ; after about three quarters of a minute the thermometer in the vial had risen a degree, viz. to 430-5." Dr. Davy relates two other experiments, of which the first was performed on the venous blood taken from the jugular vein of a sheep, the second on arterial blood. The three experiments with venous blood showed that when agitated with mercury and air for the space of a minute, venous blood was heated to the extent of 1° Fahr., whilst the arterial blood was heated only half a degree.

Dr. Davy quotes Sir Charles Scudamore, who, in his . Essay on the Blood,' at p. 59, states that venous blood cools much more slowly in oxygen gas than in atmospheric air ; that the same blood divided into two cupping-glasses, “after an interval of eight minutes from the beginning of the experiment," exhibited a difference of 8°,—that exposed to oxygen being 85°, that to atmospheric air 770

H. Nasse, in his article on Animal Heat in the fourth volume of Wagner's * Handwörterbuch der Physiologie' (1842), quotes Marchand to the effect that when oxygen is shaken with blood the latter is heated.

In a paper entitled “On the Relative Temperature of Arterial and Venous Blood,” Mr. W. B. Savory, having described at considerable length observations on the temperature of the two sides of the heart, describes others performed with a view to check the accuracy of the experiments of Dr. John Davy, and states the conclusions to which he was led by his own experiments, viz. :-1st, that when venous blood is treated, as was done by Dr. Davy in his experiments, with oxygen, its temperature was usually raised from 1° to 11° or 2°; 2ndly, that when venous blood was treated in a similar manner with hydrogen or carbonic acid, its temperature was as frequently raised, and generally to the same extent; 3rdly, that similar experiments upon arterial blood usually yielded the same results; 4thly, that in all cases the increase of temperature seemed to be the result of the agitation. In concluding his paper, Mr. Savory remarked, " At present there is no evidence upon which we can safely venture further into this inquiry. If, as I conclude from my experiments, arterial blood is warmer than venous, the increase of temperature must occur in the lungs as a result of those changes

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which the blood there undergoes. Of the nature of those changes, little or nothing is known.”

In my early researches, conducted during the months of May and June 1869, I had attempted to determine, by means of comparatively simple contrivances, whether

any heat was evolved during arterialization, making use of delicate thermometers. At first I used a glass bottle furnished with a tubulature, near the bottom in which a cork, perforated and furnished with a glass tube closed by india-rubber tubing and a clip, was inserted. The neck of the bottle was furnished with a cork perforated in two places; through one of the perforations a delicate Centigrade thermometer passed into the centre of the flask, whilst into the other was inserted a bent glass tube through which gas might be introduced into the apparatus. The bottle which I have described was filled with venous blood, both the tubes communicating with its interior being closed. It was then maintained at a temperature varying between 30° and 35° C. for many hours, until it had assumed the characteristic cherry-red coloration which indicates the complete removal of the loosely combined oxygen of the blood. The apparatus having been allowed to cool, it was invested with a jacket of felt. An india-rubber tube was made to connect the upper glass tube with a hydrogen gasometer, whilst the lower tube being opened, the hydrogen expelled any required quantity of blood. The apparatus was then shaken and the temperature determined. Then by a repetition of the process (followed in the introduction of hydrogen) pure oxygen gas was made to displace more of the blood, and the process of shaking repeated as before. The results of such experiments were eminently unsatisfactory, varying obviously with the amount of mechanical work which was formed by the experiments, and which yet did not admit of exact determination.

In some experiments I observed a heating which amounted to 00.3 C.; in other cases the difference in the readings, before the introduction of oxygen and after it, seemed to point to a cooling instead of to a heating. To give an idea of the indefinite and perplexing results which I obtained, I shall cite the details of an experiment performed on the 23rd of June, 1870, by Professor Tait and myself, the apparatus used being a tin vessel resembling in principle the one of glass which I have already described. This vessel was covered with felt, and, when shaken, it was held by means of a very strong iron clamp. Having been filled with sheep's blood, it was placed in an air-oven and maintained for a period of twelve hours at a temperature which oscillated between 1000 and 110° Fahr. It was afterwards placed in the room in which my experiments were carried on; but in order to make it cool more rapidly, its felt covering was taken off, and it was placed in water at a temperature of 15° C. It was dried, again covered with felt, and fixed in its clamp. Hydrogen was then made to expel 4-5 cubic inches of blood, which was found by spectroscopic examination to exhibit the single band of reduced hæmoglobin ; after shaking the blood and hydrogen in the apparatus, its temperature was found to be 170.8 C., then 18° C., the temperature of the air being 200.4 C. 10 cubic inches of blood were then drawn off and replaced by oxygen, which was brought in contact with tho blood by shaking; the temperature rose to 18°1 C.: more oxygen was introduced and the shaking repeated, the temperature rising to 180-25, 18o4, 1805, 180-6, 18o.6, 189.55, 1807, 180.75, 18977. At the conclusion of the experi

, ment the quantity of blood which had been arterialized was found to be 360 cubic centims. This experiment merely gave one of many results; for as long as I followed this method I was quite unable twice to determine the same

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