Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/335

 B L O

B L O

He took thirteen pounds of Iambs blood, and when the ferum was feparated, there remained fix pounds of the coagulum ; this he put without any mixture into a very large glafs retort, and diftilled it very gradually by a gentle fand-heat, till with this degree of fire there arofe no more vapours from the retort. The vefTels being uniuted, there was found in the receiver about five pints of a clear aqueous liquor, which had not the leaft mark of containing any acid. Another receiver being fitted to the retort, the fire was raifed to the utmoft degree of violence. There now came over about eight ounces of a li- quor, one half of which was of an oily nature, and the other ared fluid, fmelling very ftrong of burning. This red liquor gave equal marks ot its containing acid and alkaline particles, for it made an effervefcence with fpirit of fait, in the manner of alkali's ; and turned a tincture of turnfol red, in the man- ner of acids. The caput mortuum in the retort was a hard and light fpungycoal, weighing about five ounces. The fame experiment being tried with fheeps blood, the red liquor of the laft diftillation was fomewhat lefs acid than in the other procefs. Calves and bullocks blood, being diftilled in the fame manner, gave at the end a red acid liquor of the fame kind with the former ; but in thefe, as in the former trials, the blood of the younger animal feemed to contain a ftronger acid than that of the full grown of the fame fpecies. It is remarkable in this liquor, that the acid and alkaline par- ticles of the animal fubftance are both blended together in the fame fluid, without deflxoying one another ; which is the cafe in no other known inftance, thefe two principles always blending intimately together, and forming a third fubftance, a fort of neutral one, which is neither acid nor alkali ; but here they appear to be kept diftinct, and always ready to act upon other bodies, without any power of acting upon one another. The general rules, as to acids and alkali's, feem to hold good in the vegetable and mineral kingdoms, but not at all in the ani- mal, where the animal or vegetable acids, and the volatile al- kali's, fcem to obferve other rules, and require a certain por- tion of phlegm to fwim freely in, in order to their acting upon one another. Now in this red liquor there is very little phlegm, and to this it is owing, that they act not at all upon each other, though both are prepared to exert their qualities, on mixing with other fubftances.

Human blood being diftilled in the fame manner, fix pounds of it, when reduced to a pound and a half, by driving off the aqueous humidity, was put into a retort, and worked by diffe- rent degrees of fire up to fo great a one, as to make the retort red hot. The diftillation afforded in all feventeen ounces of li- quor ; twelve ounces of this was a red aqueous liquor, very full of volatile fait, and fmelling ftrongly of burning, and the other five ounces were oil. The caput mortuum was a light coal, weighing four ounces and an half.

On rectifying the red liquor by a fmall fire, in order to fepa- rate the volatile fait, and the aqueous humidity, there remained at laft in the retort about an ounce of a red liquor, of a ftink- ing, auftere, and very acid fmell ; this turned the tincture of turnfol to a deep red. Mr. Homberg now imagined, that the acid liquor in the blood of animals could not difengage itfelf perfectly by thefe diftillations, without addition; as the com- mon falts, fait petre, and fea fait, yield very little of their acid fpirits, on a fimple diftillation, without mixture; whereas, on barely mixing them with fome earthy matter, before they are put into the retort, they give all the acid they contain. He therefore determined to diftil human blood with an admixture of fome other fubftance ; but as earths contain a fait, which might render the operation uncertain, he determined to ufe only the caput mortuum of a former diftillation of the fame fubftance, To this purpofe, four pounds of the coagulum of human blood being well mixed with a large quantity of this refiduum, and the whole dried in the fun, it was put into an earthen retort, and diftilled in an open fire, raifed by degrees to the utmoft violence. The oil being feparated from the aqueous liquor, this was rectified ; and the effect was, that there came over four pounds of a red acid liquor, which turned the tincture of turnfol to a ftrong red. All the diftilla- tions before mentioned of the red liquors being mixed toge- ther, and feparated from their yet remaining oil, by diluting with water, and careful filtration, were at length diftilled to- gether ; the liquor that came over was as clear as water, and its firft quantities contained a great deal of volatile fait, but the two laft ounces were found to be as four as diftilled vinegar. Convinced by this, that in carnivorous and fructivorous ani- mals, and in fuch as eat vegetables alone, the acids of tbofe vegetables remained acids in the parts of the animal ; Mr. Homberg tried the fame experiments on the flefti and blood of the wolf, as a creature that eats only flefti, and on the duck and the hog, which eat indifcriminately every fort of food, and the event proved the fame in all. All contained a red acid liquor, which had the properties before defcribed, and in which the alkali and acid were fo blended together, that they deftroyed not one another, but each was ready to exert itfelf on occafion. Mem. Acad. Par. 1712.

Mr, Mery attempted to eftablifh the doctrine of air being mixed with the blood in the pulmonary vein, and being again difcharged into the branches of the trachea by the fmall branches

of the pulmonary artery. His principal argument was, that air blown into the trachea, paffed by the pulmonary veins into the heart ; and that by blowing air into the pulmonary artery, it could be forced into the trachea. Mr. Bulffinger obferved from experiments, that water thrown in at the trachea, ran out at both the pulmonary artery and vein, which neither milk nor air would do. Water injected into the pulmonary artery, patted into the trachea, and pulmonary vein, which air alfo did ; water injected into the pulmonary vein was pufhed with difficulty, but at laft ran into the trachea, and not into the pulmonary vein. Hence he concludes Mr. Mery's experiment, and confequently his fyftem, to be falfe. See Comment. Acad, Pctrop. T. 3. p. 230.

Boerhaave extends the proportion of the ferum of blood to £ parts of the whole mafs a ; yet Dr. Morgan fcruples not to de- part from this, and all thofe mentioned in the Cyclopaedia, and makes the cruor and ferum equal to each other b. Indeed in cold, and fufficiently coagulated blood, the tough crafla- mentum, and its furrounding fluid, ferum, are ordinarily found to the eye pretty nearly equal to one another =.— [ a Med. Eft". Edinb. T. 2. p. 90. b Morg. Phil. Princ. Med. P. 3. Prop. 1. p. 406. ' Boyle, Phil. Works abr. T. 3. p. 212, 460. Med. Eft. Edinb. T. 2. p. 91.] Blood 7tiicrofcopically examined — Blood makes a very common object for microfcopical obfervations. The method of exa- mining it is this ; take a fmall drop of warm blood immediately from the vein, with the nib of a pen, or a hair-pencil, and fpread it as thin as poflible on a plate of glafs ; and applying this to the microfcope with the fecond, or firft magnifier, the globules will be all feen very diftinctly, and a little practice will enable us to form a judgment on the alterations that may hap- pen in the fize, figure, or colour of them. If a little warm water be applied to the blood, the globules will be divided, and many of them break into a number of final ler globules. If warm milk be added iuftead of water, the larger globules will, be {ecn very diftinct ; but this fmaller will be blended with, and loft in milk, which is itfelf no other than a congeries of fuch globules. Baker's Microfcop. p. 112. The mixing of different poifonous and medicinal liquors with the blood may be of great ufe, but the experiments muft be carefully made, and the apparatus all got ready before the bloodis let out of the vein, becaufe if it be fuffered to coagulate firft, no judgment could be formed of the effects of the mix- ture.

Mr. Cowper examining by the microfcope a folution of opium, found its diflblved particles in the fhape of fringed globules ; whence he concludes, that fuch particles circulating in the mafs of blood, may eafily be entangled in its ferum, and thicken it in fuch a manner, as to retard its velocity, when over vio- lent, and render its motion calm and equal, whereby all pain- ful fenfations will be taken off ; and, from the fame principles it is eafy to account for its other effects, and to conceive how too great a number of fuch fringed globules muft caufe a total ftagnation of the blood, and confequently be the occafion of death. Phil. Tranf. N° 222.

A little blood being mixed with about four times its quantity of fal volatile oleofum, and viewed by the microfcope, there is feen an immediate feparation of the globules. They are imme- diately feen much diminifhed in number as well as fize, and feem quite diflblved away, only two or three being often left out of twenty in a minute. It is probable hence, that fal vo- latile, taken inwardly, may retain the fame power, and by that means prevent coagulations of the blood. Late writers have purfued the globules of the blood to a great length ; and found divers orders of them : thofe large ones vi- fible to the eye conftitute the globules of the firft order ; each of which, according to Lewenhoeck, is compofed of fix fmaller fpheres, cluftered together in a very regular way ; and that (o nicely, in a perfect globule, that the compofition comes to be imperceptible d . But fometimes the fame perfon has feen a red globule loofening and breaking into thefe compounding fphe- rules ; and fometimes has had the good fortune to perceive thefe running together, and beginning the compofition of a new red globule. Thefe fmaller fpherules they call globules of the fecond order. But Lewenhoeck did not ftop here; he faw in the chyle and blood a great many particles fix times lefs than thefe globules of the fecond order, and thirty-fix times lefs than the great red globules. So that the globules of the fecond order are to be looked on as compounded of thefe fmaller ones ; which therefore arejuftly to be reckoned as another clafs, or globules of the third order =. Further, he finds innumerable blood-vends in the body, of fuch fmallnefs, that none of thofe hitherto mentioned globules could pafs ; fo that it feems necef- fary to fuppofe inferior clafies of globules of the fourth, fifth, fixth, csfa orders. He even faw veftels, the widenefs of which was lefs than the eighth part of the diameter of a red globule ; fo that the particles pafling through them, fhould be upwards of five hundred times lefs than fuch globules, and confequently fmaller than thofe of the fourth order. What is more, upon a careful examination, he could perceive ftill fmaller veflels, narrower than the tenth part of the diameter of a red globule, and confequently not capable of tranfmitting fpherules greater, than if a red globule were broken into a thoufand parts f. On

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