THE EFFECT OF ACIDS AND ALKALIS ON 
THE GROWTH OF THE PROTO- 
PLASM IN POLLEN TUBES 
By Francis E. LLovp* 
McGill University 
In 1915 it was shownt that the protoplasm of pollen grains 
acts in the presence of acids, alkalis, and salts in general accord- 
ance with the behavior of the biocolloid gelatin. The evidence 
then secured appears to indicate that the amount of swelling is 
greater in acids than in alkalis, and less in salts than in pure water: 
from which, in the light of MacDougal's experiments, the prepon- 
derating protein component of the complex may be inferred.{ It 
soon became evident, however, that the amount of swelling for 
various concentrations of solution of the reagents used was not 
constant, and it was found necessary to determine this relation 
for an assumed analog, gelatin, and then to find the material and 
method by which the comparative behavior of the protoplast in 
the living condition could be studied. The results of the measure- 
ments of the swelling rates of gelatin in a number of acids and 
alkalis, and these in combination with certain salts have been 
reported upon in general form.$ These are in brief as follows: 
I. Theswelling rates differ in both acids and alkalis for different 
concentrations. The maximum rates are found at certain con- 
centrations above ca. N/640, which are higher for organic acids 
than for inorganic acids. At higher concentrations “ repression " || 
occurs. The higher rates are at first at higher concentrations, 
but as time elapses thé rates at successively lower concentrations 
* The writer acknowledges the assistance of a subvention from the Cooper Fund 
for Medical Research, McGill University. 
T Lloyd, Е. E. Carnegie Inst. Wash. Ann. Rep. for 1915. 
$ Lloyd, F.E. Trans. Roy. Soc. Canada, 1917 (In press). 
|| Procter, H. R., & Wilson, J. A. Jour. Chem. Soc. London 109-110: 307-319. 
1916. 
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