SECTIONAL TRANSACTIONS.— D. 5f;3 



acidity, and addition of narcotics, in concentrations sufficient to arrest the heart's 

 movements, did not reduce the oxygen consumption below the normal resting value. 



The resting metabolism of the heart appeared to be much more resistant to the 

 .action of drugs than was the metabolism associated with contraction 



The drugs mentioned were found to depress in an equal degree the oxygen consump- 

 tion associated with contraction, and the mechanical response of the heart. 



We did not find any certain exception to the general rule that the mechanical 

 response of tlio heart is proportional to the extent of the chemical change associated 

 with contraction. 



Prof. B. A. McSwiNEY and Mr. R. E. Tunbridge. — The Viscosity of 

 Smooth Muscle. 



The alterations brought about by electrical stimulation, pH, and drugs in the 

 viscous properties of mammalian smooth muscle, chiefly strips from fundus of cat 

 and rabbit, have been studied by methods similar to those described by Gasser and 

 HiU. 



Electrical stimulation, pilocarpine, histamine, acetyl choline, and barium increase 

 the viscosity of the muscular strip. Under certain conditions, atropine abolishes any 

 increase in viscosity due to pilocarpine. 



The effect of pR is very slight within the range pR 6.0-8.4. Such changes as 

 occur are in the same direction as are the alterations in length within this range 

 described by Newton and McSwiney. Lowering the hydrogen ion concentration to 

 within the neighbourhood of pB. 5.0 causes a small but definite increase in the viscosity 

 of the muscular strip. Extreme alterations of ^H, such as < pK 2.0 or > pYL 10.0, 

 cause a marked diminution of both the elastic and viscous properties of the muscle. 



The alteration in viscosity obtained on addition of pilocarpine and electrical 

 stimulation and atropine depends upon the degree of tension which the muscle is 

 allowed to develop ; on the other hand, the increase of viscosity with barium chloride 

 and histamine is dependent upon the amount of drug added. 



Monday, September 10. 



Prof. J. W. Mayor. — On Studies of the Effects of X-rays on Heredity. 



Prof. W. C. M'Intosh. — Abnormal Teeth in the Rabbit. 



Messrs. B. Heron-Allen, F.R.S., and Arthur Garland.— On the 

 Pegididce, a New Family of Foraminifera linking up the Globigerinidce 

 and the Rotalidce. 



In 1826 d'Orbigny recorded in his Tableau Mithodique a Foraminifer from Mauritius, 

 to which he gave the nomen nudum, Rotalia dubia ; no description nor figure was 

 published, and the type specimen remained ignored in Paris until, in 1914, we had 

 occasion to examine the d'Orbigny collections. About the same time we rediscovered 

 the organism in dredgings ofi Portuguese East Africa, but in the absence of sufficient 

 material we decided not to publish the matter. Since then we have discovered other 

 allied forms and have found it necessary to establish a new Family for their reception. 



The Pegididce are perforate Foraminifera of wide distribution, but of very rare 

 occurrence. They are characterised by abnormally thick-walled tests enclosing a few 

 chambers only, set in opposition to each other. The aperture is distinctive and unlike 

 anything hitherto known, sometimes occupying nearly a quarter of the whole surface 

 area of the shell, and presenting very highly specialised features. The Pegidida 

 appear to occupy a position between the Globigerinidce and Rotaltdm, havmg features 

 common to both but no very evident relationship. They inhabit the troubled water 

 on the edge of coral reefs, and they may represent an attempt at the evolution of a 

 type capable of existuig under conditions unfavourable to most hyaline Foraminifera. 



Mr. J. F. G. Wheeler.— CAangfes in the Condition of the Blubber of Blue 

 and Fin Whales. 



Averages of measurements of the blubber for metre length-differences for each 

 species and sex obtained during four seasons' work at whaling stations show a small 

 general increase in blubber thickness with increase in length of whale. 



oo2 



