Page:Cyclopaedia, Chambers - Volume 1.djvu/260

 BIO

and Mixture of the feveral Parts ; as is the Cafe in a Dia- betes, and, perhaps, in a Chhrojis, where the Shod is thick and torpid : On the other hand, where the Akalious are too redundant, the Shod is render'd too thin and fluid, to rhat the Difference of its conftitucnt Farts is loft.

Another Affect ion frequent in the Stood is, a too great abundance of Oils, or faline Particles, by means whereof the active Parts of the Shod are too much clogg'd, and thofe Parts which fhould be fecreted for peculiar TJfes in the Bo- dy, are detain'd 5 and perhaps the Solids, thro which it paffcs, too much lubricated, their Tone vitiated, fhrunk, relax'd, %$c. whence that Sluggifhnefs and Inactivity of ve- ry fat People. The contrary Aftecfion to this is, the defect: of Oil in the Shod; which being, as it were, its Balfam, lines and preferves the Parts from being fretted and corro- ded by the Salts, whole Spicula, or Edges, are, as it were, fhcathed in this foft Balfamick Matter, and their Attrition againft the folid Parts prevented. This State of the Shod is ufually attended with a general Atrophy, and a Fretting and Corrofion, of fome particular Parts ; whence ferous Deflu- xions, Apoilhumations, and Ulcers, efpecially in the Lungs, whofe tender, veficulous Subftance is more eafily annoy'd than any other, by the Acrimony of the faline Serum,

There are other lefs confiderable Affections of the Shod, rcfulting from its Temperature and Mixture, with regard to the earthy Parts ; the Confluences of which are, the Stone, tSf. and others that don't originally fpring from any Dyfcrafy, or undue Mixture of the Elements, but from an Alteration in its Motion ; fuch as an Augmentation, or Di- minution, of its progreffive Motion, or the like Changes in its elaftick Motion ; whence fupernatural Fermentations are induced : The Occasions here may be various ; ibmetimes Fevers, and other Diforders occafion'd by Surfeits, De- bauches, catching Cold, violent Exercife, &c. whence Ato- nias ; at other times, fome latent Malignity of the Air, whence Epidemical Difeafes.

The 'Shod thus variouily compounded and circumftantia- ted, vifits even the minuteft Parts of the Body, by means of its Circulative Motion : The Caufe and Courfe whereof fee under Circulation. In this Round, thofe Particles of the Shod which conform belt to the Figure and Struc- ture of the Parts thro which they pafs, are appofited to 'em, cither for their Accretion, or for the Reparation of fuch as the conflant rapid Force of the Shod wears off.

About the Matter of Nutrition, or the Source whence the Nourifhment is deriv'd, great Cornells have arofe among the Phyficians and Anatomifts ; fome contending for a nu- tritious Juice convey 'd thro the Lungs; fome letting up the Lymph, others the Chyle, fome the Serum of the Shod, fome the Cruor, as the univerfal Sitccus alibilis, &c. How- ever, all thefe, except they who bring the Nutriment thro the Nerves, make the Shod the Vehicle, that conveys the Alimentary Parts thro the Body, whatfoever they be, and whencefoever derived : But, perhaps it was on the fcore of its Heterogeneity, or Compofition of different Elements, that they did not make it felf the Nutritious Fluid, with- out reftraining that Faculty to fome particular Parts thereof. But Di.ZJrake makes no Scruple to fay, that the Shod, in its largeft Acceptation, as confuting of all the Parts before defcribed, is Ample and homogeneous enough for the Pur- pofes of Nutrition ; and that every Part thereof contributes fomething, either materially or inftrumentally, to the Au»- mentation, or Reparation, of the Parts thro which it pafles. See Nutrition.

For the Manner in. which the Shod is form'd, and how the Chyle is affimilated mtoShod, fee Sanguification.

The Quantity of Shod in a human Body, has been vanoufly ettimatcd by various Authors. Where note, That in Computations of this Kind, not only the Fluid coritain'd in the Veins and Arteries, but alfo that in the Lymphomas Nerves, and the other Veffels fecreted from it, and re- turn'd to it, are included. This Dr. Lower computes, in an ordinary Man, at about 20 Pounds ; Dr. Movlin at about ,V of the Weight of the whole Man, which may amount to about 8 or to Pounds : But Dr. Kcill, from a more ac- curate Calculation, built on the Proportion of the Coats to the \effels, fhews, that in a Body weighing i«o Pounds, 100 Pound thereof are Shod. Hence he propofes a Me- thod of determining the Velocity of the Shod : For, as each Ventricle ol the Heart is capable of receiving an Ounce ot Shod ; being full in their Diaftole, we may Tup- pole they throw out about an Ounce each Syfiole. Now the Heart beats about 4000 times in an Hour; therefore'

ery Hour 4300 Ounces, or 250 Pound of Shod, paffes

ro the Heart. So that a Quantity of Shod equal to the

( no)

BLU

th

whole Mafs, paffes in two Hours and a half: but, the Sum of the Sections of the Branches of an Artery being always greater than that of the Trunk, the Velocity of the Shod will conliantly decreafe as the Artery divides ; and the Ratio of its greateft to its lead Velocity in the Arteries may be thus found, as 5225 to r. Again, the Veins are to the Arte- ries, as 441 to 524; wherefore, as the Shod returns to

the Heart by the Veins, its Velocity will be ftiil further di- minifh'd, and may be found to move more flowly in the Veins than in the Aorta, 71 rS rimes. Again, the farther the Shod goes off the Heart, the more ilowly it returns The Times of thefe are directly as the Spaces, and reci procally as the Velocities ; confequently, fome Parts mav be fome thoufands of times longer in returning to the Heart than others. From the Diameter of the Aorta, and the Quantity of Shod driven out every Pulfe, the Velocity of the Shod in the Aorta is eafily determin'd, and found to be at the rate of 52 Feet in a Minute. But Dr. Jurin fhews, that in any two Arteries tranfmitting equal Quanti- ties of Shod, the Momentum of the Shod is greater in the Artery more remote from the Heart than in that nearer ; and that its Momentum is greater in all the capil- lary Arteries together, than in the Aorta ; and, laftly, that the Momentum of the Shod is greater in any of the Veins than in the Artery correfponding to it ; and therefore great- er in the Vena Cava than the Aorta.

Laftly he fhews, that the Momentum of the Shod in the Vena Cava, is equal to that of the Quantity of Shod thrown out into the Aorta at each Syfiole, whofe Velocity is fuch as wou'd pafs the whole Length of the Arteries and Veins in the Interval of Time between two Pulfes ; and that the abfolute Momentum of the Shod in the Cava without any regard to the Refiftance, is equal to the Mo- mentum of a Weight of 30 Pounds paffing over the Space of an Inch in a Second. But note, that the Motion of the Shod is here fuppofed equable, which in reality it is not. See Heart.

As to the Transfulion of the Shod of one Animal into the Veins of another, firft fet on foot by Dr. Lower, fee the Method and Effects thereof under Transfusion.

In the 'Phihfopbical FranfaQions we have feveral very uncommon Inftances of ipontaneous Sleeding ; particularly of a Child that lied at the Nofe, Ears, and hind-part of the Head, for three Days i, from that to the fixth, the fweat Shod from the Head ; on the fixth, bled at the Head, Shoulders, and Wafte ; and for three Days more continued to Heed at the Toes, Bend of the Arms, Joints of the Fin- gers of each Hand, and at the Fingers Ends till fhe died : After her Death were found, in the Places whence the Shod iffued, little Holes like the Prickings of a Needle. For the Stanching of Shod, fee Stiftick. '

Blood of Jeftls Chrift, a military Order infiituted at Mantua in i<$o8, by Vin. Gonzagua IV. The Devife of this Order was, tDomine probafli me; or that, Nihil hoc trifle recepto. Hermant fpeaks of this Order, and obferves it took its Name from fome Drops of the Shod of Chrift, faid to have been preferv'd in the Cathedral Church of Mantua. Their Number was reftrain'd to 20, befides the Grand Mailer ; the Office whereof was attach'd to himfelf and his Succeffors.

There is alfo a Congregation of Nuns at (Paris call'd by the fame Name, reform'd from the Sernardines BLOOD-LETTING. See Phlebotomy. BLOOD-SHOTTEN, a Diftempet of the Eyes, where the Slood-Vejfels are greatly diftended, fo as to make the Eyes appear red.

BLOODY-HAND, one of the four kinds of Trefpaffes in the King's Foreft, by which the Offender being taken with his Hands or other Part bloody, is judg'd to have kil- led the Deer, tho he be not found Hunting or Chafing BLOSSOM. See Flower. 6

BLOWING ofGlafs, one of the Methods of forming the divers kinds of Works in the Glafs Manufacture. 'Tis perform'd by dipping the End of an Iron Pipe in the mel- ted Glafs, and blowing thro it with the Mouth, according to the Circumftances of the Glafs to be bhixn. See Glass.

BLUE, one of the Primitive Colpurs, otherwife call'd Azure. See Colour.

•the 'Painters Blue is made different, according to the different kinds of 'Paintings. In Limning, Frefco, and Miniature, they ufe indifferently Ultramarine, blue AJhes, and Smalt ; thefe are their natural Slues, excepting the lait, which is partly natural, partly artificial : See each un- der its proper Head. In Oil and Miniature they alfo ufe Indigo -prepared; fee Indigo ; as alfo a factitious Ultra- marine, which fee. EnameJlers and Painters on Glafs have Slues proper to themfelves ; each preparino 'em af- their own manner. See Enamelling, and Painting on Glafs.

Blue of the Dyers, is one of their fimple, or Mother- Colours, ufed in the Compofition of others : 'Tis made of Woad, Indigo, and a <Paftel brought from Normandy : Of the three, the Taftel is efteem'd the beft, and the molt neceffary : Woad, tho of lefs Force and Effeft, yet makes a tolerable Colour : Indigo only makes a fpurious Colour ; yet^ it may be ufed along with Taflel, if it be well pre- paid, and ben't mix'd in too great a Proportion. Woad having but little Subftance, can neither be ufed alone, nor is it capable of correcting the Indigo, without the Aflif- j tance