The Protoplasmic pH of Living Cells.

Abstract

The intra protoplasmic pH of Amoeba and of cells from different tissues of Necturus and the Frog was obtained by injecting with the micrurgical technique solutions of Clark and Lubs' indicator dyes. This method allows the use of dyes which cannot penetrate living cells from without, a situation which obtains for the majority of indicator dyes. The protoplasm tolerates only a limited amount of the injected fluid. If too much is injected the protoplasm undergoes visible disintegration, with the production of an acid which the dye immediately registers. As long as the cell remains alive the final tint in the protoplasm is always the same. The Neeturus and Frog were slightly anesthetized by immersion in etherized water. They were then removed and pieces of the various organs were carefully teased in blood serum. Determinations of pH were made on the cells of ciliated epithelium, gastric and intestinal mucosa, liver, pancreas, striated muscle, and unripe ova. The pH values obtained were the same for every cell: viz., 7.5 ± 0.1 for the nucleus, both normal and injured; 6.9 ± 0.1 for the normal cytoplasm; and 5.3 ± 0.2 for the injured and cytolyzing cytoplasm. These results are in close agreement with those obtained on the starfish egg. Variations of pH found by previous investigators may be accounted for by the fact that in most of the determinations crushed cellular tissue was used. The low pH values obtained were probably due to the acid produced by injury. On the other hand, the higher pH values can be explained by the presence of variable amounts of alkaline (pH 7.4 to 7.6) interstitial fluids and blood.