LUNGS. 



It proves that the contaA of extraneous red blood does not 

 injure the cerebral funftions. He then opened the jugular 

 vein and carotid artery of a dog, received the blood of the 

 former in a fyringe heated to the temperature of the body, 

 and injeifted it into the latter. The animal was almotl im- 

 mediately agitated ; the refpiration was hurried, and the 

 diftrefling kind of fuffocation that belongs to afphyxia was 

 produced. Soon all the fymptoms of the latter ftate ap- 

 peared ; the animal life was entirely fufpended j the lieart 

 ftill continued to beat, and the circulation went on for half 

 an hour, at the end of which time the organic life alfo was 

 extinft. This experiment was often repeated, and inva- 

 riably with the fame refult : about fix ounces of black blood 

 were injeded. If the point of the fyringe was infertcd into 

 the vein, fo as to draw up the blood without any poffibility 

 of its coming in contaft with the air, the refult was the 

 fame, except that death came on rather more (lowly. 

 Various other fubftances, fuch as ink, oil, wine, water 

 coloured blue, urine, bile, mucous fluids, produced the 

 fame effects. That the fatal effecis arife in thefe cafes from 

 the aifiion of the black blood, J^c. on the brain, and not on 

 the internal furface of the arteries, is proved by injefting 

 them into the crural artery ; the injection is never morral, 

 although numbnefs and even paralyfis generally follow. If 

 blood be taken from the carotid artery of an animal who 

 is fufferinor afphyxia, and injefted into that of another, the 

 fame effects with thofe already mentioned are produced. 

 Alfo, if the carotids of two dogs are united by a lilver tube, 

 fo that the heart of the one fends its blood to the brain of 

 the other, and a (lopcock be placed in the trachea of the 

 former, no bad effeft is produced, fo long as that remains 

 open. Clofe the (lopcock, and black blood will be fent 

 inftead of red. Now, the dog whofe carotid receives this 

 blood becomes coiifuled and agitated, drops his head, and 

 lofes his fenfes ; but thefe phenomena come on more (lowly 

 than when black blood taken from the venous fyftem is in- 

 jefted into the artery. If the transfufion be ftopped, the 

 fymptoms of afphyxia may go off, and the animal recover ; 

 but death invariably follows the injeftion of blask blood 

 with a fyringe. 



In fumming up his experiments, Bichat concludes, that 

 the nature of the principles contained in the black blood 

 render it either incapable of exciting the aftion of the brain, 

 or aftually injurious to the organ ; but he cannot decide 

 whether its influence is exerted negatively or polltivcly. 



He proceeds to make fome interefting obfervations on the 

 nature and treatment of afphyxia. " We might conclude," 

 fays he, " from the above-mentioned facts, that the beil mode 

 of treating thofe who are fuffering from afphyxia, would be 

 to impel into the brain red blood, which is its natural lli- 

 mulus. Two points of time fhould be di(liDgui(hed in 

 afphyxia; i, that in which the central funftions alone are 

 fufpended ; 2, when the circulation as well as the movements 

 of the chell have ilopped ; for, in this affeftion, the animal 

 life is firft fuddenly extinguilhed, and the organic ceafes 

 after a certain interval. In the (irll of thefe periods, the 

 transfufion of red blood towards the brain, from the carotid 

 of another animal, gradually re-animates the powers of mo- 

 tion ; the cerebral funftions are partly rertored, and the 

 arrival of blood in the brain is often announced by fiidden 

 agitations of the head, eyes, &c. ; bnt this improvement 

 foon difappears, and the animal relapfes if the caufe con- 

 tinues, as for example, if the (lopcock in the trachea re- 

 mains ihut. On the other hand, if the (lopcock be opened 

 in this tird period, the arrival of frefli air in the lungs al- 

 moft always gradually re-animates thefe organs. The blood 

 affumee the red colour, and is fent in that Itate to the brain, 



and life is reftored without transfufion, which is completely 

 ineffedtual in the fecond period of afphyxia, that is, when 

 the organic movements, particularly thofe of the heart, are 

 fufpended. The transfufion of red blood towards the brain 

 does not, therefore, afford us any remedy in the cafe of 

 afphyxia. Neither does it fucceed after the injeftion of 

 venous blood into the brain by means of a fyringe, which is 

 invariably fatal. Afphyxia produced by injecting blood 

 taken from the vein into the brain is more prompt and cer- 

 tain, than that occafioned by the gradual chan-je of the red 

 into black blood, confequent on interrupted refpiration ; 

 and the nature of the two caies is manifelUy different." 



The phenomena of afphyxia, as obfcrved in the human 

 fubject, coincide very well with what is obferved in experi- 

 ments on animals. In all cafes the brain is fird affeAed, its 

 functions are annihilated, and the animal life, particularly 

 fo far as regards the fenfes, ceafes ; the internal functions 

 are fubfequently arreftcd. When afphyxia is produced in. ' 

 an animal with an artery open, it is curious to obl'erve how 

 the affciftion of the brain coincides with the change of colour 

 in the blood, while the energy of the heart is unabated. 

 Moft of thofe who have been expofed to afphyxia, and have 

 efcaped fuffocation,. have experienced only a general kind of 

 benumbing or paralyfis, the feat of which is manifelUy in 

 the brain ; while all in whom the pulfe and heart have 

 ceafed to beat, certainly die. Almoll all who have re- 

 covered fay, that they felt firft more or lefs violent pain in 

 the head, produced probably by the firft contact of black 

 blood with the brain. Bichat confiders the common notions 

 of the effects of charcoal vapours on the head, and the ex- 

 pre(rions concerning the heavinefs, giddinefs, &c. produced 

 by them, as ftrong proof that the firft influence is in fac't 

 exerted on the brain. He obferves further, that many indi- 

 viduals who have recovered from afphyxia produced by this 

 caufe, exhibit, for a longer or (horter period, various 

 affeftions of the intelleftnal funftions and voluntary mo. 

 tions, as for inftance confufion of ideas, and unfteady mo- 

 tions of the lower hmbs ; the fame effefts, in a fmaher 

 degree, which apoplexy produces more fenfibly. Convulfive 

 motions have fometimes taken place almoft immediately after 

 expofure to mephitic vapours ; and a pain in the head has 

 often lafted many days after the difappearance of the other 

 fymptoms. 



From the foregoing confiderations, Bichat deduces the. 

 following conclufions ; i ft, that when the chemical pheno- 

 mena of the lungs are interrupted, the black blood aft» 

 upon the brain as upon the heart, that is, by penetrating its 

 tilFue, and thereby depriving it of the excitation neceffary 

 to its aftion; 2dly, that its influence is much more promptly- 

 exerted on the former tlian on the latter of thefe two 

 organs ; 3dly, that the inequahty of their influence deter- 

 mines the difference obferved in the ceffation of the two 

 lives in afphyxia, where Uie animal always ceafes before the 

 organic. Hence we may infer, how unfounded the opinion 

 is, that in thofe who are executed by the guillotine, the 

 brain ilill continues to live fome time, and that fenfations of 

 pleafure and pain may ftill be referred to it. The aftion of 

 this organ is intimately connefted to its double excitation ; 

 ift, by the motion, and zdly, by the nature of the blood 

 which it receives. As this excitation is fuddenly interrupted 

 m that mode of death, all feeling is as fuddenly fufpended. 



Influence of the Death of the Lung on that of the Organs of the 

 Body in genrra!. — Bichat commences his view of this lubjeA 

 by examining the changes of colour which the blood under- 

 goes when the chemical phenomena of the lungs are in-, 

 terrupted. He found the hell method of obferving thefe 

 changes to be by fixing a llopcock ia the trachea of an 

 4 M 2 animal. 



