Abstract
Gunn 1 has devised a mechanical system for transuding liquids through living membranes. The regulation and maintenance of a definite negative pressure in this system is based upon the method of Wade and Merriman 2 employing a variable air gap. Using this apparatus, Gunn tried the effect of the transudation of caffeine citrate and of Eschis venom on rabbit mesentery. The results were negative in that no change in rate was observed with these substances when compared with the rate obtained with Locke's solution itself.
The apparatus has been simplified and improved, and in its final form provided for a complete glass assembly. (Fig. 1.) Using this improved apparatus I have carried out experiments to determine
Living mesentery of freshly killed rabbits was used as the membrane. The procedure is essentially that of Gunn. The piece of mesentery, which had been previously placed in Locke's solution, is tied over the muslin-covered opening of a special tambour and transudation is begun after the tambour is fastened in place on the apparatus. To obtain a “normal curve” transudation is continued for 15 minutes under a pressure of 150 mm. Hg. at 26°C. Using a standard Locke's solution the transudation rate falls steadily with time. The beaker of Locke's solution is replaced by another containing Locke's solution to which has been added the desired concentration of lysin or salts to be tested. Transudation is continued and a new curve for the rate is obtained. Comparing the curves it is then possible to determine the change in transudation rate and thus the relative porosity of a given piece of mesentery.
I. SSaponin. Transudation for 15 minutes in ordinary Locke's solution yields the “normal” hyperbolic transudation curve (Fig. 2).
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