Researches upon the anatomy and physiology of respiration in the Chelonia / by S. Weir Mitchell and George R. Morehouse.

  • Mitchell, S. Weir (Silas Weir), 1829-1914.
Date:
[1863]
Catalogue details

Licence: Public Domain Mark

Credit: Researches upon the anatomy and physiology of respiration in the Chelonia / by S. Weir Mitchell and George R. Morehouse. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

    10/50
    authorities, we were surprised, on afterwards learning the singularly truthful views of Townson, to find they had fallen unappreciated, and that, in many instances, tin) had not even been honored by a notice, or, when so noticed, had been men- tioned onlj to he condemned. Physiological Observations ox the Amphibia. Dissertation th<- Third, on the Respiration of the Tortoise, Robert Townson. The first inspection of the structure of the animals I have lately treated of, tin? Etanee and Salamandrae of Linnaeus, will show that respiration cannot he performed in them as it is in man and animals similar to him; the absence of the osseous parts and diaphragm is sufficient to demonstrate this; and though, on the records of physiology, there are instances of the continuation of respiration after the mobility of the osseons parts had ceased, yet, as these were onlj instances of suffering nature, where the accompany ing assistant, the diaphragm, still continued in full energy, phy- siologists ought, likewise, in examining the structure of the animals I am now to treat of, the Tortoise-tribe, to have suspected that this function was not performed in them as it is in us. Yet these hints given by this anomalous structure have either been, neglected or made an improper use of, and the manner of their respiring remains in the greatest obscurity to the present hour. Before I proceed to show the present state of our knowledge on this subject, by giving the opinions of the celebrated anatomists and physiologists who have written upon it, 1 will just ohscrvc that, as the impossibility of respiration being performed in the frog-tribe, in tin; usual man- ner, consists in the absence of the ribs and diaphragm, so here the immohility of the whole hones of the trunk, and absence of the diaphragm, form the insuperable hindrance, and not a deficiency of solid parts as in the preceding; for a modifica- tion of the ribs and sternum here envelops the whole animal. The diaphragm, though said hy some to exist, is really wanting. Blasius, however, asserts its existence, and descrihes it thus: Diaphragma insignc admodum, oblique a pectoris anteriore inferioresque parte sursum adscendct, lateribus primo, hinc dorso firm iter adherens; altiorem adeoque situm in posticis ohtinet, quam in anticis, contra ac in homine, canibus bohus aliisque animalihus observamus, ubi anteriora sublimem majis locum habent posterioribus. Membranosum hoc totum notatur, similiter ac in avibus varus deprehendimus, nullis tibris carneis manifesto gaudens. Distinguit equidem thoracem a ventre inferiorc, ast non sit in animalihus aliis: Pulmones enim cum hie sese in hoc magis, quam illo ventre exhibeant magne parte, diaphragmate hand includuntur, imo vix aliqua parte. Extendit se supra hepar partesque alias ipsi adsitas, usque ad vesicam urinariam cui valide adeo unitur tota superficie supe- riore ut non nisi magno artificio scparari queat. Superius pericardio jungitur. But I am convinced he has taken the peritonaeum for it. I have sought for it in vain, as well as other zootomists; neither Gotwald nor \Yallbaum has observed it, and the French academicians, who dissected one near five feet long, say, that la tortue a non settlement son ecaille, qui lui sont lieu de thorax, absolument immobile, mais nous ne lui avons trouve n'y de diaphragme, n'y d'autres parties qui puissent Bupplier a ce mouvement. This deficiency of the requisite mechanism for respira-