SECTIONAL TRANSACTIONS.—I. 427 
anastomosing the carotids, feeding of either one of the pair, two or three days 
after the union, the animals being otherwise normal (conscious), produced no 
gastric response in the other. This confirms earlier observations (but under 
anesthesia) carried out on cats (Lim). It affords no evidence of a hormone 
(Edkins) mechanism. 
We suggest that the mechanism in all cases might be a primary local 
vascular change—i.e., increase of blood flow in the celiac stem. The evidence— 
viz., increased temperature of the stomach, increased volume of the spleen 
_ when the stomach is distended, increased volume of the intestine when another 
: 
segment is dilated—is incomplete, but is in part supported by the stromuhr 
observations of Burton-Opitz. 
9. Prof. F. H. Scorr.—Respiratory Variation of the Arterial Blood 
Pressure. 
10. Popular Lecture by Prof. J. C. Drummonp on Cod-liver Oil. 
Friday, August 8. 
11. Joint Discussion with Section J (q.v.) on Physiological and Psycho- 
logical Factors of Muscular Efficiency in Industry. (Page 436.) 
12. Prof. H. B. Speakman and Mr. A. H. Gex.—The Influence of Metallic 
Chlorides on the Growth and Metabolism of Y east. 
Yeast cells are able to grow and to ferment sugar in wort containing up to 
10 per cent. of salt. With increasing concentrations of salt there is a progressive 
inhibition of cell division, with no growth stimulation even in very dilute solu- 
tions as is the case when a synthetic medium is used. If a sufficiently small 
number of cells are used as inoculam the maximum rate of gas production is 
stimulated by low salt concentrations, suggesting that this stimulating influence 
is only exerted on those cells produced in the medium. 
The ratio between yeast crop and sugar fermented changes with the salt con- 
centration, showing that the inhibition of growth and fermenting capacity are 
independent. The weight of CO, produced per gram of sugar utilised diminishes 
as the salt concentration increases, an indication of abnormal physiological 
changes. Associated with these results we have found a gradual increase in 
the nitrogen content of the yeast cells. 
13. Dr. Guitrorp B. Reep.—The Influence of Salt and Hydrogen Ion 
Concentration upon the Growth and Structure of Bacteria. 
The growth of several species of bacteria in dilute peptone or pure protein 
solutions is increased with the addition of NaCl to a maximum which varies 
with the species. ‘he addition of the salt widens the pH tolerance. Further 
increase in the concentration of NaCl decreases the growth and decreases the 
_ pHi tolerance. 
In very dilute NaCl and at optimum pH for growth the organisms are of a 
characteristic form, at pH higher or lower than optimum the organisms vary 
in structure, usually they are larger, and at the extremes of pH for growth 
consist of still wider structural variants from the characteristic form. In the 
optimum NaCl concentration for growth the organisms are more nearly typical 
in form with less variation in structure at the extremes of pH. In concentra- 
_ tions of NaCl above optimum for growth the organisms are all atypical in form, 
_ with conspicuous modifications in structure at the extremes of pH. 
14, Prof. G. N. Srewart.—Colour Phenomena caused by Inter- 
mittent Stimulation with White Light. (Demonstration.) 
Attention having been called to studies on subjective colour phenomena caused 
by intermittent stimulation with white light published by the author in 1888 
_ (Proc. Roy. Soc. Edin., 1888, 445-464), many unpublished data obtained then or 
