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when the intermediate spaces are test blach, and the ouilines of the glands brought prominent ly into vi eW. The Same glands may be rea lilyseon in the boiled bra ins of sishes and birds, their structure in allanimais being the fame. Joan. Pseit, according to Joan. Kentinan, seems to have anticipaled this discovery in his observation Os a Stone found in the brain, Whicli sione Was a conglobate of minute roundisii acini, of a cineritious color, and very like a mulberry. It is probable thalit Was produced by petrifaction of the cortex, the natural figure of the glands thereos being preserved. These cortical gland 8, tortuoiastyplaced, mahe up the eXterior gyres of the cerebrum, and are appendedio the medullary fibres Or vesseis arising theres rom; so that Whereverthe gyres are cut across, a determinate and firm mass of glands is alWays soland overi ying the medulla: and this is stili more evidently the case in the cerebellum. And the substance of the cortex is of the fame character in the ventricies of the brain, and at the beginning of the spinal marroW; for aster botling, it has the sorin and exhibiis thecharacteristic substance of the glands, being exactly similar in theserespecis to those in the exterior region of the brain; but stili there isthis disseretice, that the former glandS are Set among the eXeurrent nerv-ous bodies or fibres, the protuberances of the ventricies heing made upos nervolis vesseis With cortical glandes among them; and in the insideos almost the whole spinal marrow, the cortex described elseWhere) has the Same glandular character, and is everyWhere supplied by blood-vesseis ; and in that part of the spine that issues froni the cerebellum and cerebrum, Under the pons Varolii, at the supposed ventricle of the cerebellum, cortical glaniis of the Liud are scatterest abolit in di ferent places; sor under the externat Surface, Whicli is fibrous and nerv- Ous, a large portion of them lies concealed, and particularly under the pons Varolii itself; and Soon after We find litile portions .of the fame glands hidden withiu, commixed With the medullary substance. 77. It may be doubted whether the brain be framed on the fame modet as the liver, Which, as We have stated, ' is in sume cases dividedinto numerous lObes, and is made up of Other tesser iobes, as it Were glandular portions, Whicli are thenaseives further subdivided into minute acini, in Whicli at last the vesseis terminate. This I say may be doubted, for is you take froni the cerebrum and cerebellum the nervolis fibriis OfWhicli the medullary substance consists, you have nothing test but glandS,each separate froin the other, and whicli forni the mass of the corteX,
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and perhaps correspond in structuro to the lobules of the liver: althoughon the other haud it is stili a question whether the glandular SubStaneeSof the brain are not conglobated of other minute paris, in the manner So evident in the liver. But the lucidity and Whiteness of the brain, themueOus character Of iis substance, and the minuteness of iis glandS, elude the poWers of the microscope, and there re We cannot decide thesubject by an appeal to the senses : at any rate Ne leave it to Others more SagaciOus than Ourseives, to be cleared up by accident rather than Study;
in the meantime thiuking it probable that these glands of the brain may be conglobated of the fame acini. me Cerebri Cortice, cap. i.)
Wharton ... is os opinion that the substance of the brain is disserent froin the substance of glands, because the brain is more Sost, tender, pure, and friable than the glands, and is moreover lubricolis and white. . . . But SOme of the glands are also sost, as the thymus in Foung chil-dren, and the pancreas; and furthermore among the glandS theniselves there is a disseretice of more or less in this respect; the conglomeratebeing SOfter than the conglobate. . . . In thς nerves too, We find the Same diversity in color, sos iness, and friability; for at their origin froni
numerous ramifications Of arteries and vetus, Such, in faci, as are not to
a Single vesset runs iis course inside the ventricies. Vet it is a universalrule, that every single gland of the cortex is supplied by the extreme endsos both arteries and vetus. In the more persect animais then we sud, that the blood-vesself, by means of the meningeat membranes, irrigate the extreme glauds of the cortex of Whicli the gyres of the brain arecompoSed, SO that a netWork of vesseis is seen in the pia mater, the twigs 1 rom Whicli penetrate the intimate substance of these cortical glands ; and heuce, When the pia mater is torn aWay, the SOft structure of the glands is injured to no stight degree ; and When the glands them-selves are cui, red potuis are stili seeu whicli communicate With the
79. Τhe intermixture and combination of the nervous fibres in thecerebellum produces the arborescent appearance described by Cortesius and othors, and which also I find is exactly repeated by nature in thecerebrum. For is the gyres of the cerebrum With their cortex be cui orturn acrOSS, the Same appearance of a tree With iis branches and bark,
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will be presented. This may be eastly veri fied by mahing a transverse
section of the entire cerebrum, Or of any one of itS PariS. . . .
ventricles, and at the beginning of the spinal marro , where the interior prominences are Siluated; and Since, Wheu these prominences are laidopen, fibres continuous With the nerves are brought into vi0W, We are necessarily led to inser that the nervos are in faci produced si om these interior glaniis; and there re, although the fibres of the optic nervesseem to ruti a stili farther course, in the cerebrum and cerebellum, Jetas they adhere Strongly to the cortical prominences of the Ventricles, perhaps they have their root to some extent in these also. Ibid.,
atmosphere is ever so stightly vitiated or altered as Hippocrates intimates in his book, De Morbis Saeris,) the brain is the sirst part to sympathige, and to Undergo a change of state. And the fame thing happens is the humors contained in the arteries admit any incongruous mediey of eX- ternat things, or is the proslared blood is not of the right composition, in Whicli case those disorders of the head sollow that are described by
Hippocrates in his book De Glandulis. . . . Sometimes theSe cortiCalglaniis are injured by externat WoundS, as noticed by SurgeonS, and con- Siderable excrescences arise, Whicli froin their analogy are called fungi; but Whicli are produced, perhaps, by the extravasation Of the nervous juice, Whicli in consequence of Some disruption Of the passages of the cortical glands, is not excreted into the nerves by a continuOUS paSSage, or at least is not conveyed bach by the veliis ; but escaping froni iis vehicle, and ali other bonds, it readily coagulates and occasionS a tumor, as we constantly find in other paris Where tumors arise, stoin the potiringin os determinate particles in too large quantities. Ibid., cap. iv.)
was the first, is Ι am not mistahen, Who observed the disserenoe and division in the parietes or mass of the brain: in fact he called the cineritious or bluisti White substance that sirst medis the eye externalty, thethe brain proper; and the enclosed white and more solid substance, hecalled the medulla : and these substances, which he sound to be discriminaled from each other by their respective color and solidity, and by Special interstices Or lines, he separated with great dexterity in animaisneWly Lilled. . . . In the more perfeci red-blooded animais, and in allthe larger fishes that have hitherio come under my notice, I have invariably observed this cineritious substance, termed the cortex. It iS
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animais a portion os it is placed around the outermost appendages of thecori HS calloSum ; the rem aining portion being dispersed about in the Ventricles, particularly at the origin os the spinal marroW, Where Fou Willsind litile fringe-like pieces of the medullary and White substance of thebrain disseminated and enclosed; and the eminences that make the ventricles falcated are formed by the cortex. Anil, furthermore, in the oblong tract of the spinal marroW, ouiside the brain, you Will See this Same cineritious Substance, not indeed placed at the ouiside, but in the
ti OUS substance or cortex ; for that pari Whicli is connected to the Varicose appendages from Whicli the spinal marrow is generalty supposedio begin, and Whicli is prolonged towards the anterior part of the brain, is at sirst cineritious, and asterWariis is succeeded by the white substance that be re lay under the cortex, and occupies nearly the half of the ventricte, but finalty is again covered by the cortical substance comitigup froni below, and in Whicli there are singular plexuses of bloOd-VeSSelS. In the brain of these fame fishes, at the beginuing of the Spinal marro Where there are tWO appendages, One On each side, analogous to intestines in forni, the cortical substance is generalty mingled With the medullary. In the more perfeci animais this cineriti us substance silis the exterior region of the brain with varicose ducis resembling intestines ; sor Whenthe medullary substance aster forming the ventricies Within it, produces the corpus callosum, it gives out appendages Whicli come beyond the externat Sursace, and are not unlike the mesenteo stripped of the intestines ; around Whicli appendages the cineritious cortex is Spread ; Sothai as it covers these varicose appendages on both Sides equally, it resembles a long gyre os intestines. But in the cerebellum, as iis productions are propagated in the Way of laminae placed One Uponanother, and the outgoing branches are sent on both sides equally
It is extremely dissiculi to determine the nature of this cineritious Substance, sor We see in it nothing solid derived from the coagulation os the red blood ; nor do the senses inform iis even of iis organigation. Vetit iS probabie, . . . that it contains at least minute channeis through Whichthe blood particles ruri, and as it appears comparatively sost and mucoUS,
it is also probable that it dissers greatly froin the medulla of the bratu
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round wllicli it is spread. And is We are to attribute any parenchymatous structure ut nil to the brain, sor prOpping the vesseis and other organic paris sent through the viscus, the substance of the cortex Mould readi ly suggest itself to us as of that hilid, since it seems to resemblemoss mingled with clay. Dissertatio Epistoliea de Cerebro. 983. V1 EUASENS. The brain consists of two disserent substances, namely, the cineritious and the white. The cineritious, Whether in iis natural State, or after it has been boiled in Water or Oil, is much soster than the white ; and when closely examined through the microscope, isseen to be composed of innumerable globules, ali combined together, and toa certain extent os an ovat figure; So that it nearly resembles a body madeup os conglobate glands. TheSe glandS mutuatly compreSs each Other, OceaSioning ObtuSe angies, as observed by the learned Μalpighi ; Whichan es are separated from each Other by almost eques intermediate spaces.
Τhis is proved by the foll0wing experiment: Tahe spirits of Wine colored blach, and potir it upon the cortical substance of the bratu after it hasbeen bolled, and stripped os pia mater. Υ0u will then sind the fluidenter so fur into the litile spaces interpo sed belween the externat glandsos the cortical substance, that after it has been gently Wiped aWay by apiece of fine mustin, innumerable litile portions os it Will be eastly seen
position as not to have even the Smallest space belween them to receive any portion of the darii spirits of Wine. - Iore ver the brain hardens When it is flowly boiled in oti, . . . and is at this time any of the particles of Whicli the cineriti us substance is made up, are Separated fromeach Other, they are never Seen extended or placed longitudinalty. In Whatever manner they are draWn apari, or pulled aWay from each other, oven is they are broken bes ore being inspected, they in no caSe appeartapering, but rather shortened and as it Were contracted into them Selves. Yet this would not be so is the particles Were of any other figure than ovat or oblongO-rotund. We theres ore assert with Hippocrates, that thebrain, in part at least, is glandular. . . . The head,'' SayS he, also has iis glands, namely, the brain, Whicli is similar to a gland. V . . . And
cineritiOUS Sub Stanee . . . either occupies the exterior paris Oi the cerebrum and cerebellum, . . . and penetrateS deeply into their medulla, . . .
or is found in the very middie of the cerebrum, . . . Or in the meduli Roblongata; . . . and where it Occupies the exterior paris, it is calledeither the cortex, or the cortical substance, or the eX ternat cineriti0uS Or
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glandular substance: but Where it is found in tho inside of the viscus, it has no other nam es than the cineritious Or glandular Substance. V Neuroyr phia Univerδalis, lib. i., cap. X.)
os light to pass them Without refraction; contra to What they do in the Other or medullary part of the brain, in Whicli they are so dispo Sed that tho light catinoi pass them in right lines, and consequently being a
puted, that even the 64th part of a myriad, i. e.) of a ten hundred thousanditi part of any substance but as big as a s mali grain os sanit, cannot, especialty is os a rigid or inflexibie nature, enter those litile
veSSeis, are diScovered to malae up both the cortical and medullary partos the brain. As also further, that even the tender coats of the smallest Of tho se vesseis Whicli contain the asoresaid most minute globular fluidbodies, are also fuit Os yet far more minute vesseis, than they them selvesare.V Ibid., p. 96.)85. RUYACII observed in the cortical substance When placed under ater, particles of disserent forms, Which he considers to be nothing morethan the juicy extremities of minute arteries, and whicli extremities, although they are continuations os arteries, yet by reason of their Sosinessare so uni ted as to present the appearance of a distinet and peculiar Sub Stance. insist. Anat. Xli., Expl. tab. Xiv., fg. I.) While these vesseis arefloating in clear Water, their extremittes represent an infinite number Ospenciis and fascicles, and their last threads whicli are sillod With injection, appear to assume a disserent figure.* φ86. of ali the discoveries,V says Ruysch, that I have made Withinthe last sorty years, the folloWing is the greatest, namely, that the cortical substance of the brain is uot glandulati as anatomisis have Wrongly
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degenerate in various places Without any intermediate substance intovesseis of a disserent character.' V Verheyen, Corp. Hum. Anai., lib. i., tr. i., cap. Viii. : See alSO RUySch, The8. Anat. Vi., n. 73.)87. It is Worthy os consideration, says Ruysch, that the arteries of each convolution of the brain, anastomose aud unite Uith the arteries nexi them . . . . And it is to be noted of the circumgyrations convolutions of the brain While stili covered With pia mater, that they are by
Bidloo's imaginary and chimerical delineation of the glands of the cortical
Epist. Anat. ix.) The reader Should by ali means consuli the plates of this author, as Esiat. xli., tab. Xiv. XV.), Where he Shews the litilethreads that, after his particular proceSS of maceration, are dra n out in continuity With the arteries; the membranouS connexioris being entirelydestroyed, and the order disturbed, SO as to produce the appearance of an immense quantity of VeSSel S. See alSO his Epist. Anat. vii ., tab. viii., fig. 2, 3), Where he Shews that the processes of pia mater invest-ing the cerebrum are of a Serpentine Shape, While those investing the cerebellum are falcisorin ;' also fig. I.) that the inner sursace of the pia mater exhibitS a moSSy covering of Vesseis Whicli insinuate themselves into the cerebellum. See particularly lat. Anat. ix. and Xli., tab. X. xiv. XV.), the appearance of the loculi Or thalami of the cortical substance With in the Serpentine processes of the pia mater nexi to the sursace of the brain. 88. ΡΑCCHIONI. Is you to uch the cortex of the brain With your
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finger, you Will not fuit to notice that it is extremely sinooth, and coveredWith as it were a most subito Oil; a fact Whicli I have learni, not Without Surprise, from very frequent dissections. The truth of this is broughtto Ocular demonstration in cases of concretions and hydatids of the lymphatics of the pia mater, in Whicli Ue so metimes see the oit soating
Vallisueri not long ago remi ded me of an observation made by the diligent Ri sch, to the effect that the pia mater . . . is in VariouSplaces enriched with sat.' Ibid., p. li8.) Bellini first instituted an examination Os human lymph, of Which he enumerates three degrees orspecies, namely, the lymph of the blood, the lymph of the lymphatios and thoracio duci, and finalty the lymph of the brain. Ue particularly noticed that is the two first species of lymph were submitted to the
poraled in sinoke; but that the third species of lymph in the brain, When Similarly treaten, produced no bubbles, and test no coagulated
portion, but altogether evaporated and vanished. Zambeccari also RSSureS US, Dom his OKn observations, that there is a certain liquid in the ventricies of the brain and spinal marrow, Which does not coagulate
by heat, but entirely evaporates. Ibid., p. 89.) Aster Fou have care- fully opened the cranium, and laid bach a considerable portion of the
dura mater froin the front to the occiput, or to either Side, but So as topreServe the mUre important attachments of the two membranes und of
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arius and legs about in ali directions, unconscious Os What he was dOing. . . . AS While he was alive there Mere no sigiis Os percussion in the integuments of the hoad, so after he was dead we could find none in the Shult, or the paris underneath it. On proceeding to examine the brain for the seat of the disease, we at ouce discovered it in the dura mater. On the lest fide we found a considerable bladder, Which at frst deceivedus, for Opposite iis convexity we sam a Lind of sinuous recess in the dura mater. But culting the membrane through, a quantity of yello isti
Serum ran Out, and we mund an analogous membranous concameration
portion os marrow lying in the proper medullary substance of the bee, by the addition or accession of Whicli the marros is dilated and formsa nodule . This portion is by no means So White as the proper medullary Substance, but is some hat grey, or os a fleshy color. Perhapstheres ore the marrow, by the intervention of this heterogeneous sub-- stance, is dilated and rendered thicher, that it may have more strengilito put forti, iis nerves . . . . Vel perhaps the dilatation has another usealso, sor the dilating matter feems to me to be of the Same character asthe substance of the brain, and ans ers to the cortical substance and the transverse fibres. Biblia Naturre, p. 5l9, 520, tab. XXli., sig. 6, 7.)Τab. XX., fg. 6, b, Shews the brain of the bee, Or rather the secondpair of cerebrat particles, and how the cortical substance of the brain is brought tuto vlew when the fibres covering it are remOVed. LetterS e, ridenote the third and fourth pair of particles, or the cerebellum, Separated from the rest, and hoW these partietes communicate With each other; but the cortical fibres that arise from them are represented in εitu insg. 4, H n H. . . . In fg. 5, 3 8, this cortical substance is seen to bedivided in the middie, although the division is covered on the otherside by a smali thin membrane. . . . The marrOW then . . . in fig. 5, Π,
appears placed in the most beautis ut Way betwoen the cortical sub-StanceS, and at the fame time we may see hoW it communicates, and is united in pari With the cortical substance. Ibid., p. 497, 498, &c.,&c.) See also Malpighi's observations on this substance in the silkWοrm in his Diraert. Epistolio. de Bombyce.'
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90. BoguΠΑΛvΕ. These arteries of the bra in are interWoven in sirin Order in the pia mater, as in an incredibiy thin basis, or arachnoidWeb, and from every p int thereos send down tWigs almost perpendicularly, Which tWigs inter eaving and anastomosing With oach other liketheir arteries, generate as it Were a membrane, Whicli, by iis insinuation, sortiis sulcated and deep gyres, by Whicli the exterior of the cerebrum and corobollum is dividen almost down to the medulla; but the cerebellum less deesty than the cerebrum. These ridges, convoluted in the formos intestines, a re again resolvable into Other similar tesser ridges; and areali framed by the insinuation of the pia mater, but have red vesseis on their Outer Sursace Only, Such Vesseis being merely applied to their inner substance. This inner substance for the most part is not tingod with redat nil, as it never admitS any Sanguis erous artery Or vein ; and as for that portion of it Which remains in the cerebrum and cerebellum, after theyhave been injected With WaX, macerated in Water, and freed by abrasionor shahing ' from ali the paris that the injection has not penetraled, itappears to be a congeries of minute vesseis, like flock or doWn, so sost, juicy and tender as to breali With the least sorce imaginabie, and dissolve into a pullaceous humor barely by suspending them in plain Water. 9l. This exterior, cineritious, sost, humid substance, is termed the cortex of the cerebrum and cerebellum. Ιt on ali sides exactly investsthe whole origin of the other and internat substance, Whicli is very White, solid and less juicy, and is termed the medulla of the cerebrum and cere- bellum ; Wheres re the medulla clearly appears to arise primarily froin thecortex, both in the appendices, the Ventricles, the crura, and the medulla oblongata. But in the inside of the spinal marrow there is a substance similar to the cortex; which likewise is altogether arteriai, but is surrounded by the medullary Substance inversely to the former case. In the cerebellum these two sub Stances are SO QOnSpicUOUS, that Fou maythere plainly perceive the Way in Whicli the medulla proceeds froin thecortex, With iis proportion, fabric and divisions ; and you Will also constantly Observe, that the cortex of the cerebellum is harder and yellowerthan that of the cerebrum. 92. Since, theres ore, at every strohe of the heari, a Very large portion
pelled by a poWersul and direct force into the cortex, the lalter must beactualed by a certain Alight systole and diastole, So long as these vesselsare fuit of blood. But there must also be Venous VeSSeis everyWhere present at the ends of the arteries, although their membranes are toothin, and they themselves are too sinati, for them to be visibie; and there