. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PERMEABILITY OF ARBACIA EGG TO AMMONIUM SALTS 173 permeable to these ammonium salts, and that the mechanism of the penetration is that predicted. 8. FIG. 8. The swelling of Arbacia eggs in M/2 solutions of ammonium acetate of the pH values indicated beside each curve. Abscissa?, times in minutes ; orcli- nates, diameters in units each equal to ;. (See Footnote 1 concerning the pH values used.) The solutions of ammonium salts were made up by adding to half normal NH4OH sufficient concentrated acid to give the pH de
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PERMEABILITY OF ARBACIA EGG TO AMMONIUM SALTS 173 permeable to these ammonium salts, and that the mechanism of the penetration is that predicted. 8. FIG. 8. The swelling of Arbacia eggs in M/2 solutions of ammonium acetate of the pH values indicated beside each curve. Abscissa?, times in minutes ; orcli- nates, diameters in units each equal to ;. (See Footnote 1 concerning the pH values used.) The solutions of ammonium salts were made up by adding to half normal NH4OH sufficient concentrated acid to give the pH desired. The volume changes produced in this way were slight and the resulting solutions could be considered, with little error, to have a salt concen- tration of M/2, or approximately that of sea water. In some cases, where hypertonic solutions were desired, the salts were made up in bicarbonate-free sea water instead of distilled water. To obtain this, cc. of normal HC1 were added to a liter of sea water, and the CO2 was driven off by aerating for twelve to fifteen hours. The pH was brought up to neutrality by the addition of a little NaOH and then the ammonium salt was prepared as before. The half molar solutions made up in distilled water were isosmotic with the cells, and penetration of salt from them could be detected by the swelling of the eggs, which proceeded until they were destroyed. The solutions in bicarbonate-free sea water, on the other hand, were initially hypertonic so that the eggs shrank, regaining their original size gradually only if the salt penetrated. The volume changes were studied by the method described in the pre- ceding paper (Stewart, 1931). II The experiments were divided into two main series, one in which the ammonium salts were made up in pure M/2 solutions and another in which they were dissolved in sea water or half molar KC1. (NaCl could not be used because of its toxicity in unbalanced solutions.) The advantage of experiments of this secon
Size: 1832px × 1364px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
