experiment was repeated with the same result, the peritoneum being immersed in water.

Dr. Bright, in support of his belief that the leather creak is a diagnostic sign of adhesions, relates several cases. None but those in which post mortem examinations were made, can of course be received as satisfactory. These are four in number, and it is necessary to examine them to ascertain how far they support Dr. Bright's belief in the connexion between the leather creak and adhesions, or how far they are in accordance with the explanation now offered of the production of this sign.

In case No. I. there was a complication of morbid states, a cerebriform tumor in the abdomen, with adhesions and lymph on the peritonæum; so that, as Dr. Bright himself observes, it was impossible to determine to which among them the creak was to be referred.

In case No. II. there was a large ovarian tumor, and in the situation where the creak had been perceived, there was found on dissection, adhesion between the tumor and the peritonæum, but this is not satisfactory. The creak was perceived in the month of February, and the patient lived until the December following. The adhesions being found in December is not proof of their having existed ten months previously; the interval is too long, and there is no mention made of the sign having been perceived at any time nearer to the date of the post mortem examination.

To case No. III. the same objection applies, and more strongly; for the creak was observed in July, and August 1830, and the patient lived until November 1834. There is moreover, almost positive evidence that at the time when the creak was perceptible in this case, there could have been no adhesion. It was detected in July 1830, immediately after tapping: there could hardly have been adhesion of any amount, at the time when the peritoneum contained so much fluid, as to require that operation. The post mortem examination in November, 1834, however exposed adhesions so close and so extensive, as

almost to obliterate the cavity of the peritoneum, so that in cutting away the parietes the intestines were perforated. Such adhesions it is obvious, must have grown up subsequent to the tapping in July, and after the date of the presence of the creak. If the creak were dependent on adhesions, it ought instead of vanishing, to have become every day more marked in proportion as the adhesions became more and more perfect, but on the contrary, there is no mention (in the notes of the case) of the creak having been perceived after August 1830, from which we may fairly infer that it had ceased to exist.

In case No. IV. the operation of tapping was also performed, three gallons of fluid were drawn off, and two days after the creak was perceived. "It was perceived but for two or three days, and then became indistinct." This occurred in April, and the patient lived until June. On the post mortem examination, the colon and omentum were found adherent to the abdominal parietes. It is more than probable, that in this case, as in the one preceding it, the adhesions were formed in the interval between the operation of tapping and the death of the patient; and that the creaking which was perceptible for only two or three days, was caused only as long as the lymph shed on the surface of the peritoneum was as yet unattached to the opposing surface. If the adhesions had been the cause of the creak, there is no reason apparent why it should not have continued perceptible up to death. A fifth case is also related communicated by Mr. Hutchinson, but the observations already made apply to it, a period of six weeks having elapsed between the period when the creak was felt, and the death of the patient.

All the cases related by Dr. Bright, leave us in doubt, whether to attribute the "leather creak" to the presence merely of lymph which had been shed preparatory to the formation of adhesions, or to those adhesions fully formed. Adhesions were it is true found after death, but we are not therefore justified in

concluding that they had existed at the period when the creak was felt, or in referring the creak to them; for a considerable interval having elapsed between the period when the creak was perceptible and the death of the patient, these adhesions might have grown up within that interval. The doubt in which we are left by those cases, is cleared up by the case related in this paper. In the progress of that case, the creak was frequently felt, and after death no adhesion having been found, it necessarily follows that adhesion is not necessary to its production, for it is scarcely possible to suppose, that if adhesions ever had existed they could have disappeared.

The conclusions which may be drawn from the case related in conjunction with Dr. Bright's cases are, that "crepitus or creaking" is not diagnostic* of hydatids as supposed by Recamier and Piorry, nor of adhesions as supposed by Dr. Bright himself, but that the doubt expressed by him is well founded; and lastly, that deposition of moderately thick and consistent lymph on the peritonæum, is the only condition requisite for the production of the "leather creak," which deposition of lymph may or may not terminate in adhesions.

Indeed a careful examination of all the cases noticed, proves not only that this sign " is not necessarily connected with the existence of adhesions, but that as long as the creak continues to be felt, adhesions are not yet formed. Some of Dr. Bright's cases very strongly support this conclusion. The creak was perceptible in them for two or three days after tapping, and then ceased to be felt; that is, it was perceptible as long as the lymph which was to form the adhesions was yet soft and yielding, and then ceased when the adhesive process was completed. This conclusion is also supported by analogy with what occurs in similar instances, for example in pericarditis, the new leather

* I do not mean to assert that an analogous sensation may not be caused by hydatids in the manner described by Piorry, but that it must not be esteemed a diagnostic sign of them, since it may be produced by another cause.

creak being perceptible only while the recent deposition of lymph is yet soft and spungy.

What is wanted in cases occurring to one observer, may often be furnished by another, and thus in the present instance, the cases related by Dr. Bright, and the case detailed here, throw a mutual light upon another, and enable us to arrive at an explanation of a physical sign, which probably neither observer could of himself have attained. The determination of the extent of diagnostic information given to us by the leather creak in diseases of the abdomen is of considerable importance; for as the existence of adhesions in the peritonæum might occasionally considerably influence practice, a mistake on this point might involve life, in the treatment of some of the most serious abdominal diseases. I should not omit to mention that Dr. Beatty, by his acuteness of tact, anticipated without the aid of dissection, the explanation of the production of the leather creak, which has now been drawn from pathological investigation.

ART. XVI.-Outlines of certain Changes of Organic Elements. By Sir JAMES MURRAY, M. D., Edinburgh, and T. C. D.; Member of the Royal College of Surgeons, Edinburgh; Senior Physician to the Lord Lieutenant.

[Read at a Meeting of the Surgical Society of Ireland, 20th Feb. 1836.] GENTLEMEN,

HAVING had the honour of taking a part in a discussion at the College of Physicians, respecting the evolution of urea in the blood, and the detection of various saline products in the urine, I have been induced to invite further attention to subjects so interesting.

As the discussion alluded to took place on the evening before last, the shortness of the time, will, I hope, excuse the imperfections of this paper.

My object is to elicit information from those whose studies are more immediately directed to organic chemistry.

The elements composing the inorganic world are few and simple, and their combinations intelligible, but the investigation of the elementary mutations of organic matter encounters difficulties at every step. Here we meet such boundless variety, such perpetual change and complexity, that we cannot reduce their combinations exactly to the same order of laws, which regulate the simple arrangements of mineral bodies.

The rule of definite proportions, however, is our great auxiliary in unravelling many of the intricacies of anamolous modifications otherwise almost inexplicable. The atomic doctrine has brought chemical laws nearly within the calculations of mathematical reasoning, and enables us to class chemistry among the exact sciences.

The human body is composed of particles or molecules called immediate or proximate principles. In the fleshy or soft parts these constituents are chiefly fibrine, gelatine, and albumen.* These principles are composed of four ultimate essential elementary bodies, carbon, oxygen, hydrogen, and nitrogen. These four elements combine to form the above principles in certain specific proportions. In round numbers these definite quantities unite in the following ratio, per cent:

The proximate principle of bone is mostly phosphate of lime, the elements of which are lime and phosphorus with

The questions of the identity of albumen and gelatine, and whether the one be naturally a product of the other, are not here entertained.