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ceding signs; as it will then be our best guide, in cases II. Moving where we have determined upon emptying the vessels as powers of

the sanguifar as we can do it without danger. Hardness and soft- neous sysness of the pulse, together with that vibratory thrill tem. which has been called wireness, are not quite so easily Hard and

soft pulse. learnt as its fulness and smallness, but a nice finger will readily discriminate them, and practice will point out the difference to every one. These characters Dr. Fordyce makes dependent, and I think with great reason, on the state of the arteries rather than on that of the heart, or on the quantity of the circulating fluid; and Mr.John Hunter concurs in the same view. They measure the degree of vascular tone, or power of resistance; and when the same effect, whether above or below the natural standard, takes place in the capillary arteries, it produces that change in the pulse which he distin- Obstructed

and free guished by the names of obstruction and freedom, but pulse. which it is not always easy to discriminate from several of the preceding qualities; nor is it of great importance, as we have in such cases other symptoms that more strikingly manifest the same fact. Thus far, perhaps, the doctrine of pulsation may be Examples of

the doctrine studied to advantage: but when, beyond this, we come to a distinction between the free and dilated pulse, as extreme. proposed also by Dr. Fordyce; the quick and the frequent, as proposed by Stahl*; and the dicrotic, coturnizing, and inciduous, proposed by Solanot, as mere sub

more euhPulse of varieties of the rebounding, or redoubling, itself a variety of the irregular pulse, we perplex pathology with a labyrinth in which the student is lost, and the master wanders tonopurpose. “Infida”, says Professor Frank, “arbitraria et æquivoca est multorum de pulsibus criticis doctrina." I De Bordeu acquired great reputation in the middle of Organic

pulses of De the last century, for applying the doctrine of pulsation as Bordeu. an index to the diseases of every distinct organ of the

carried to an

Solano.

• De Differentiâ Pulsds celeris et frequentis.

+ Novæ Observationes circa Crisium Prædictiones ex Pulsů. Wetsch, Medicinæ ex pulsů. Vind. 1770. Vienn. 1753.

De Curandis Hom. Morbis Epitome. Tom. 1. p. 30.

II. Moving body; whence he not only adopted most of the subdivipowers of

sions of Solano, but added others, and subdivided them the sanguineous sys still further. He started it as a new hypothesis, which tem.

he endeavoured to support by facts and arguments, that On what founded.

every separate organ possesses a principle of life in some measure peculiar to itself, and independent of the rest of the frame; that each is endowed with a proper function, and susceptible of proper sensations and movements; and that, by the agreement and co-operation of all these distinctive powers, the life and health of the entire system are built up and maintained. These principles are developed and defended in his thesis “ De Sensû genericè considerato", published at Montpellier in 1742. Though arrogating the merit of originality, they are, however, little more than a revival of the ancient doctrine of harmony invented by Aristoxenus, and at one time very popular in Greece, as we learn from Lucretius:

-Multa quidem sapientum turba putarunt Sensum animi certâ non esse in parte locatum; Verùm habitum quemdam vitalem corporis esse,

'APMONIAN Graiei quam dicunt*. How ap M. De Bordeu, in adopting this hypothesis, supposed

farther, that an affection of any particular organ will occasion a peculiar variation in the pulse from its natural state; and, by a careful attention to these changes, he conceived himself capable of ascertaining the seat of the disease, and the channel through which nature was aiming at a crisis. He describes, in consequence, an overwhelming multiplicity of organic pulses; but his general division is into superior and inferior pulses : and this he founds on an observation that the actions of the parts seated above the diaphragm, and of those below, excite very different impressions on the circulatory system. These views are chiefly given in the most famous of all his publications, intitled “ Recherches sur le Pouls

plied,

* De Rer. Nat. Lib. III. 98. See the author's examination of this hypothesis, and its resemblance to others of later date, in the notes to his Translation of Lucretius. Book V. 100 and 104.

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par rapport aux crises”*. This hypothesis became ex- II. Moving tremely popular in France and Germany, and excited a p

the sanguiconsiderable degree of attention at Edinburgh. It is neous sysnow, however, little heard of, and is by no means worth reviving.

In effect, a voluminous and complicated classification of pulses is rather a proof of an active fancy than of a sound judgement: and though Dr. Heberden and Dr. Hunter may have thought too lightly of this branch of pathognomy, it is better to adopt their simplicity than the puerile conceits of many more elaborate pulse-makers. The Chinese have a more operose system of pulsations than any that have appeared in Europe ; but nothing can be more whimsical than their divisions. Avicenna treated of the pulse musically; and Hoffenuffer, pursuing his principles, drew up, in 1641, a musical scale of the pulse, dividing it into musical time, and marking the different beats by semibreves, minims, and crotchets, semiquavers, and demisemiquavers; thus reducing his patient to a harpsichord, and his profession to a chapter on thorough-bass.

III. To speak minutely of the CONSTITUENT PRINCIPLES III. IntrinOF THE BLOOD, would carry us too far into the regions i of animal chemistry; and I shall hence limit myself to a blood. very brief analysis of those that are fixed or confinable, having already paid some attention to the gasses in the physiological proem to the preceding class. For the first judicious account of these principles, we Analysis of

Parmentier are indebted to an elaborate memoir of MM. Parmentier and Deyeux, who arranged them under the following heads:-1. A peculiar aroma, or odour of which every one must be sensible who has been present at a slaughter-house, on cutting up the fresh bodies of oxen. 2. Fibrin, or fibrous matter, frequently also called coagulable lymph, and gluten. 3. Gelatine. 4. Albumen. 5. Red colouring matter. 6. Iron. 7. Sulphur. 8. Soda. 9. Water.

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andl

Deveux.

* Paris 1756, 8vo.

III. Intrin.

Per

ties the blood. Corrected by later experiments.

No gelatine in the blood.

Still minuter and more exact experiments have since been made upon particular portions or the whole of the blood, especially by Dr. Marcet*, Dr. Bostock t, and Professor Berzelius t, which confirm the greater part of the preceding results, but have detected a few errors which it is necessary to notice.

Neither the blood of man nor of quadrupeds, so far as they have been examined, contain any gelatine. «The mistake”, says M. Berzelius, "arises from the gelatinous appearance of the albumen; I have never been able to detect a particle of gelatine in blood, and, as far as my researches extend, I have found gelatine to be å substance altogether unknown to the economy of the living body, and to be produced by the action of boiling water on cartilage, skin, and cellular membrane; substances which are totally distinct from fibrin and albumen." It follows, therefore, that wherever gelatine is found in the animal frame, it is produced by a decomposition and recombination of the particles of the blood by the action of the secernents. But instead of the gelatine, Dr. Bostock has since discovered in the serosity, or that part which remains when the lymph or serum has parted with its albumen by heat, a distinct substance which he has denominated from its quality, uncoagulable matters, and which Dr. Marcet has called muco-extractive matter. Berzelius has affirmed it to be impure lactate of soda.

The sulphur detected in the blood by Parmentier and Deyeux does not exist in a free state, but is a component part of its albumen, as is also its carbone and hydrogene, which, in consequence, have aś strong a claim to be considered as constituent principles as sulphur. It is by means of its constituent sulphur that the albumen of blood or of an egg, becomes capable of blackening a silver instrument employed to stir it. And as it is the albumen that is now known to dissolve the oxydes of mercury introduced into the blood in the care of syphilis, it is

Uncoagulable matter of Bostock.

Sulphur of the blood a component part of the albumen alone.

Chief solvent of metallic oxydes.

• Trans. Medico-Chirurg. Soc. Vol. 11. p. 370.
+ Id. Vol. I.

Id. Vol. m.
$ Elementary System of Physiology, Vol. 1. p. 476. 8vo. 1824.

matter.

O

a

probably owing to the sulphur of the albumen that this III. Intrineffect is produced; or that the oxydes of any metals in- sic proper

ties of the troduced as medicines into the blood are dissolved; since blood. the albumen of the serum is also discovered to be a powerful menstruum in dissolving iron, copper, and other metallic preparations.

The iron traced in the blood is, in like manner, a con- Iron of the stituent principle of the red colouring matter, and exists stituent of

blood a conin so intimate an union with it that it cannot be detected the colourby the best. re-agents we possess, till the composition of the colouring matter is totally destroyed by heat, or some other means. With these explanations we are now able to proceed Analysis of

Berzelius. to a clear comprehension of the following brief analysis of the blood, as corrected by the later experiments of M. Berzelius, supported by those I have just adverted to of Dr. Marcet and Dr. Bostock.

Blood is composed of two parts, one homogeneous and Blood com. liquid, and one only suspended in the liquor, and spontaneously separating from it when at rest. - The homogeneous and liquid part consists of much

Liquid or albumen and a little fibrin, both combined with soda, suspendir and all dissolved in water. It also contains a small por- part. tion of a few other saline and animal substances.

The suspended part consists of the colouring matter. Colouring It differs from albumen chiefly in its colour and its inso

matter, or lubility in serum. Iron enters as a constituent ingre- part. dient into this material, in the proportion of do of its weight. It seems to be the colouring principle; but cannot be separated from it as long as it continues to be colouring matter. This separation can only be effected by combustion, or by the concentrated acids, both of which agents entirely decompose the substance with which, the metal is combined. The iron exists in the form of oxyde, with a small proportion of subphosphate of the same. But the colouring matter cannot be artificially produced by uniting albumen with red subphosphate of iron. Fibrin, albumen, and colouring matter, resemble each Earthy

and a sus

phosphates

suspended

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