OCR Text |
Show 22 INTRODUCTION. INTRODUCTION. :flees, there are many in which the nutritive juices being ab- the composition of all the parts a d t 23 sorbed by the parietes of the intestine, are immediately dif- called nutrition Th. f .1. ' n ° effect what is properly h h l b ta f th b d d . IS act tty, which the bl d fused throughout t e w o e spongy su s nee o e o Y: ecomposing itself at ever . oo possesses, of such, it would appear, is the case with all Insects. But from precise kind of molecule y pomt, s.o .:JS to leave there the the Arachnoides and Worms upwards, the nutritive fluid circu· it is this wonder which ne~essary' Is mdeed wonderful; but f 1 d 1 h lt . t .fi t. F h constitutes the whol . lates in a system o c ose vesse s, w ose u Ima e rami ca tons or t e nourishment of th r d e vegetative life alone dispense its molecules to the parts that are nourished by than a great subdivision 0 ; :~I s we see no other arrange men~ it; the vessels that convey it are called arteries, those that but for the production offl .de ehxtreme arterial ramifications, b · · b k h f h · l t" · Th d · UI 8 rmg t e apparatus · 1 t ac to t e centre o t e Circu awn, vezns. e an varwus. Sometimes the ex . . IS more complex circulating vortex is here simple, and there double and even spread themselves over larg tr;mtties of the vessels simply tri pie (including that of the vena portre) ; the rapidity of its fluid exhales • at oth . t e sur aces, whence the produced motion is often assisted by the contractions of a certain fleshy ties. Befor: these a:;:~ loozes fr~II_l the bottom of little cavi- 11 d h h . h · l d th th ria extremities cha · · apparatus ca e a eart, w IC IS p ace at one or e o er most commonly give rise t . 1 nge mto vems, they centres of circulation, and sometimes at both of them. fluid, which appears to 0 pa~Ifcu ar vessels that convey this In the red-blooded vertebrated animals, the nutritive fluid between the two ki d pfrocee r~m the exact point of union d h . . h" d . h 1 n s o vessels • In th. h exu es from t e mtestmes, w Ite or transparent, an IS t en se sand these latter form b . ' . IS case t e blood ves-termed chyle; it is poured into the veins where it mingles ed conglomerate or se 't Y mt~rlacmg, particular bodies call-l l V I . ere ory gttands. with the blood, by two peculiar vessels called actea s. es· n ammals that have no circula . . sels similar to these lacteals, and forming with them an arrange· the parts are all bathed . th tlo?'. In Insects particularly, ll d h l h t . 1 t th p ts d m e nutritive fluid h f ment ca e t e ymp a IC system, a so convey o e venous ar raws from it what it re . . : eac o these blood the residue of the nutrition of the parts and the pro· a liquid be necessar qmres, and If the production of ducts of cutaneous absorption. up by their pores tt~ ~:o~~r vess~ls floating in the fluid take Before the blood is fit to nourish the parts, it must expe· It is thus that the bl n~ I .uent e ements of that liquid. rience from the circumambient element the modification ol tion of aU the parts andoo I~cessantly supports the composiwhich we'have previously spoken. In animals possessing a changes which are 'th rep."rs the inJuries arising from those c1· rcu I at·m g system, one portt·o n of t h e vessel s I·S d estm· e d to of t he 1· r functions Teh contmual a. nd nee essary consequences h bl d · · h. h h d · t th' · e general Ideas we fi · h carry t e oo Into organs 1n w tc t ey sprea 1t over ! ? Is process are tolerabl cle I orm Wit respect great surface to obtain an increase of this elemental influence. tmct or detailed notio f y h ar, a though we have no disWhen that element is air, the surface is hollow, and is calle~ want of knowing the c~:miw at passe~ .at each point, and for lungs; when it is water, it is salient, and is termed b1·· anc/!ire. ts ufficient precision' we canncoatl rceonmdepro sition of each part with There is always an arrangement of the organs of motion for ransmutations necessary t :ffi • an exact account of the the purpose of propelling the element into, or upon, the orgtl Besides the glands h? ~ ect It. of respiration. fiuids that are d es t"m e dwfio ICr thsee ~martaetren fIr om the blood those In animals destitute of a circulating system, air is auJLUijQILI.£.'"'ue which detach others f . 1 a economy, there are th h f h b d b I . II d . h rom It t lat are to b t 11 . roug every part o t e o y y e astic vessels ca e eit er as superB h . e ota y eJect~ chere; or water acts upon them, either by penetrating ·p rko duced by the k"1d neuyos·u osr- tf oer suormm e, for inhs tance, which is vessels, or by simply bathing the surface of the skin. ln of the cuttle-fi h d e use tot e animal, as the respired, or purified blood is properly qualified for lusca, &c. 8 ' an the purple matter of various mol- I |