The laws and mechanics of circulation, with the principle involved in animal movement . r. Itneed not be great, but the lungs must expand in order to pro-duce it. Fifteen pounds per inch is too much for thelungs, but since several ounces only is necessary, the airflowing in at the same time through the trachea for assistingit pari passu with expansion, the action is readily effected. Concerning the Action in the Trachea. —With a view of de-termining the energy in the trachea, I was led to make thefollowing physiological experiments upon the organ : As soon as a bullock had been dispatched at t
The laws and mechanics of circulation, with the principle involved in animal movement . r. Itneed not be great, but the lungs must expand in order to pro-duce it. Fifteen pounds per inch is too much for thelungs, but since several ounces only is necessary, the airflowing in at the same time through the trachea for assistingit pari passu with expansion, the action is readily effected. Concerning the Action in the Trachea. —With a view of de-termining the energy in the trachea, I was led to make thefollowing physiological experiments upon the organ : As soon as a bullock had been dispatched at the slaughter- 116 PHYSIOLOGICAL EXPERIMENT ON TRACHEA. house, but before life had become extinct, I made the follow-ing section of the trachea (Fig. 34), which shows the conditionbefore contraction sets in, which occurs some minutes later,from 10 to 15 only, or long before it invades the other struc-tures, and which is also suggestive, since it would indicate un-usual energy, in the organ. It will be seen that the organ iscircular, being nearly perfectly round. But when fully COn-. Fig. 34.—A Transverse Section of a Bullocks Trachea, made immediately after death,and before contraction had set in. A. shoulder of the cartilages where the transversemuscles have insertion ; B, extension of the thin cartilaginous plates to near themesial line (3) ; 1, mucous membrane ; 3, transverse muscles ; 3, longitudinal muscles. tracted, it presents the following appearance (Fig. 35), whichwill give some idea of the energy in the organ.* The con-traction is enormous, reducing the lumen nearly one-half,while the thin terminal plates forming the posterior portionsof the cartilaginous rings (A, B) are pulled forcibly in contact—about a half-inch space separating them (Fig 34, 3, B), and arebent upon themselves by the action in the muscles, which pullaway from the plates and put the loose connective tissue (, C) upon the stretch. It is proper to remark, that at the pointwhere the muscle
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