Osmosis experiments with living and dead membranes / by E. Waymouth Reid.

  • Reid, E. Waymouth.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Osmosis experiments with living and dead membranes / by E. Waymouth Reid. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    ment of the experiment, but that erosion of the epithelium greatly hastened its passage through the wall of the organ. He also noted a much faster passage of the salt through the wall of the intestine than through that of the stomach. Cazeneuve and Livon1 experimented with the exsected bladders of dogs which had been compelled to retain their urine for some hours before they were killed. The bladders, distended with urine, were suspended in distilled water, and the hypobromite of soda test applied to a portion of the water from time to time in order to detect the presence of diffused urea. From a fresh bladder they found that no urea had passed out by 4 hrs. after the commencement of the experi- ment. After allowing 24 hrs. to elapse before using the bladder, the presence of urea could be detected in from 10 to 15 minutes. Scraping away epithelium from within by means of a sound at once rendered the wall permeable to the contained solution of urea. They noticed more- over that the state of nutrition of the animal influenced this retarding action of the epithelium of the bladder. Englemann2, in some experiments relating to the influence of the membrane upon the process of electro-osmosis, found that the fresh skin of the frog was less permeable than skin which had remained in water for some days prior to its use. I have repeated the experiment of Cazeneuve and Livon with the bladder of the cat, suspending it in distilled water as soon as practicable after decapitation. With a normal bladder, I found no trace of urea in the surrounding water till 5 hrs. after death, by using the hypobromite of soda test; in another case the wall of the bladder was rubbed between the finger and thumb in order to detach the epithelium ; in this case urea was found within 2 hrs. after death. It is evident then that diffusion through animal membranes is greatly influenced by the physiological state of the tissues composing such membranes, a fact daily brought before the notice of the physician in cases of albuminuria of diverse origin, various pathological transuda- tions etc. Experimental evidence has been given moreover that some power of selection resides in the protoplasm of the epithelia covering certain of the cavities of the body. Tappeiner3 in a series of very careful experiments conducted for 1 Complex Rcndus, t. 87, p. 435, 1878. 2 Arch nterlandaiscs, p. 332, 1874. :1 Wien Sitzungsberichte, Bd. 77, Abtheil. nr. p. 281, 1878.