me.

sarily made it a point to certify the statement and number of page. In doing this my eye caught a reference of his to “Note sur un Cétacé Grampus griseus" par. M. P. Fisher, in Ann. des Scien. Nat. 5th Ser. 1867, p. 363. I therefore read this, and I confess with much interest. Fisher's description of the animal examined by him leads me to believe it was identical with that dissected by myself, inasmuch as colouring, streaks or scratch-marks, and form of head and body are concerned. His remarks on the stomach as well as Turner's confirm what I have above said of certain genera individually examined by Fisher tersely compares the skeleton and dentition of his supposed Cuvier's with Risso's species, and speaks of their geographical range and migrations. He sums up with four conclusions and a corollary. Without giving his own words I may curtly express his ideas as follows: 1. G. rissoanus appears in the Mediterranean about the same period of the year that G. griseus is found on the French Atlantic coast. 2. Their dentition is nearly alike the latter with 2 to 4 mandibular teeth on each side, the former 5 to 6. 3. Their bones are identical. 4. Difference of colour accounted for by its being variable, and shape by post-mortem effect. Hence he is of opinion the two species ought to be re-united, as Baron Cuvier was inclined to regard them.

It appears to me that M. Fisher from his stand-point has not overdrawn legitimate inferences, provided that it was G. griseus and not G. rissoanus he examined. As to variation of colour in what has been designated under the latter title, what I have mentioned proves, and Van Beneden and Gervais' plate shews great likeness in osteological features; so that I am prepared to find, when the latter has been carefully compared in the young and old, that they may after all be but one specific form, though Dr Gray lays stress on the black colour of his G. cuvieri = D. griseus Cuv.

ON THE SPECIFIC HEAT OF BLOOD. BY ARTHUR GAMGEE, M.D., F.R.S.E., Lecturer on Physiology at Surgeon's Hall, Edinburgh, and Physician to the Royal Edinburgh Hospital for Sick Children.

(Extract from a Report presented to the Physiological Sub-Section of the British Association. Liverpool, 1870.)

BEFORE commencing independent experimental researches with a view to determine the heat of arterialization, it appeared to me to be essential to undertake a set of experiments with the object of determining with accuracy the specific heat of blood; and it is to a notice of these that I at present confine myself, reserving the account of experiments, now in progress, on the further question of the heat of arterialization to a future occasion.

I believe I am quite accurate in saying, that the specific heat of blood has been determined by Dr John Davy alone, his experiments being recorded in his Observations Anatomical and Physiological, in a chapter entitled, "On the Capacities of venous and arterialized Blood for heat." In his experiments he made use of defibrinated blood, and employed for the determination of specific heats the methods of mixture and cooling. According to Davy, the specific heat of lambs' and sheeps' blood varied from 0·812 to 0·934 (water being 1·00).

The great discrepancy of these results made it most desirable that the experiments should be repeated in the most careful manner.

I employed invariably the method of mixture:

A flask furnished with a tubulature near its base was fixed in the centre of a water-bath, and from the flask a tube also surrounded by water opened externally by a stop-cock. This flask was filled with mercury.

The blood to be experimented upon was placed in a light and highly polished iron vessel weighing 92.15 grammes, which was surrounded by cotton-wool and placed in a glass beaker. The temperature of the blood and mercury was ascertained

before and after mixture by means of a standard thermometer made by Fastré of Paris, belonging to the Museum of Natural Philosophy of the University of Edinburgh, divided into fifths of a degree centigrade, and capable of being read to one-fiftieth of a degree.

In my experiments warm mercury was added to blood at a lower temperature. The specific heat was determined by the usual formula:

c = coefficient of the specific heat of blood.

M =

weight of blood.

Tits temperature.

m = weight of mercury.

t = its temperature.

c' coefficient of specific heat of mercury, i. e. 0·033.

=

=

temperature of mixture of blood and mercury. μ specific heat of iron vessel.

=

The results of my experiments are exhibited in a tabular form below:

* This blood had a specific gravity 1058 at 55·7 Fah. Solids per 1000, 213.10.

As a check to the accuracy of the method and apparatus employed in the above experiments, I determined the specific heat of mercury by means of it, substituting water for the blood used in my previous experiments. Only two experiments were performed.

μ = 10.48 C=1 c = coefficient of sp. heat of mercury.

The above determinations were all made with the perfectly fresh blood of the ox. They may, I think, be taken as representing very accurately the specific heat coefficient of the blood. They shew that the specific heat of blood is not, as Davy supposed, considerably below that of water, but almost exactly the same, the mean of all my results giving the coefficient of the specific heat of ox-blood as 1.02.

A knowledge of this was essential to the further progress of the research on the heat developed during the arterialization of the blood, with which I am at present engaged.

RESEARCHES ON THE CONSTITUTION AND PHYSIOLOGICAL RELATIONS OF CYSTINE (C,H,NO,S). BY JAMES DEWAR, F.R.S.E., Lecturer on Chemistry, Veterinary College, Edinburgh; and ARTHUR GAMGEE, M.D., F.R.S.E., Lecturer on Physiology at Surgeon's Hall, Edinburgh.

AMONGST the rarest and least understood of the proximate principles of the animal body, must undoubtedly be placed the substance which forms the subject of the present paper.

Cystine is a body which is best known as a constituent of urinary calculi, and of the urine, and which has been stated to exist in the substance of the kidneys. When present in the urine, cystine generally deposits after some time in the form of individual hexagonal plates; sometimes these are grouped together in large masses and exhibit a great tendency to adhere to the sides and bottom of the vessel in which the urine is contained. These crystals are readily soluble in solution of ammonia, which may be used as a convenient re-agent for separating and purifying the substance.

Although occurring in the urine, there can be no doubt that its presence is very rare, and when it does occur it is in the urine of persons who are the subjects of the so-called cystine diathesis, i.e. in whose urine it has a great tendency to make its appearance.

Sometimes the individuals who are the subjects of the socalled cystic diathesis are apparently less robust than they should be, whilst in other cases nothing is observed to indicate any disturbance in the functions of the body, until urinary symptoms point to the existence of a calculus.

The sweat undoubtedly contains cystine in some cases. One of us had the opportunity of detecting cystine in the perspiration of a man under the care of Professor Maclagan in the clinical wards of the Royal Infirmary, and we are in a position to state positively that in cases where cystine is present in the urine, silver coins carried in the pockets of the patients have been observed rapidly to become blackened.