374 SECTIONAL TRANSACTIONS.— I. 



Afternoon. 

 Demonstration (with Section D, q.v.) in Prof. Hogben's Experimental 

 Laboratory, 



Thursday, July 25. 



Joint Discussion (Sections D, I, K) on The Nature of Life (General 

 the Rt. Hon. J. C. Smuts, P.C. ; Dr. J. S. Haldane, F.R.S. ; Prof. 

 L. T. HoGBEN ; Prof. H. Wildon Carr ; Prof. E,. F. A. Hoernle ;: 

 Prof. G. Bargee, F.R.S. ; Prof. E. C. C. Baly, C.B.E., F.R.S. ; Sir 

 Daniel Hall, K.C.B., F.R.S. ; Prof. A. S. Eddington, F.R.S.). 



Friday, July 26. 



Discussion (Sections B, I) on Vitamins.— Tvot E. Mellanby, F.R.S. ; 

 Prof. A. Harden, F.R.S., &c. 



Dr. H. Zwarenstein. — Nitrogenous Excretion in Xenopus Lcevis. 



The urine of Xenopus (the South African clawed frog) was collected every twenty- 

 four hours. Urea, ammonia, creatine, creatinine and traces of uric acid were found 

 to be present. 100 c.c. of urine contain 70 mg. urea, 28 mg. ammonia, 2.5 mg. 

 creatine, and 0.20 mg. creatinine at 20° C. Each frog excretes on an average 5 c.c. of 

 urine per day. Decreasing the temperature to 5° C. causes an increase of about 

 100 per cent, in both creatine and creatinine. 



Previous attempts by various investigators to demonstrate the presence of either 

 creatine or creatinine in amphibian urine have been entirely negative. The amount of 

 creatine in the blood was 1.40 mg. per 100 c.c, but the presence of creatinine therein 

 was not definitely estabhshed. 



Dr. L. P. Bosman. — Carbohydrate Tolerance in Xenofus Lcevis. 



JOHANNESBURG. 

 Wednesday, July 31. 



Prof. A. D. Stammers.^ — Some Influences of Light on Physiological 

 Functions. 



Mr. W. B. OsBORN. — Preliminary Observations to Determine the Ultra-Violet 

 Content of South African Sunlight. 



Mr. L. E. Hertslet.^ — The High-Veld Climate from the Heliation Angle. 



Dr. T. M. Mavrogordato and Dr. J. S. Haldane, F.R.S.— TAe Effects 

 of Dust Inhalation. 



Thursday, August 1. 



Dr. R. S. Creed. — Some Recent Work on Reflex Action. 



Mr. E. N. WiLLMER.— TAe Nutrition of Cells growing in vitro. 



Mrs. M. Mellanby." — Some Factors controlling the Structure of the Teeth 

 and their Susceptibility to Caries. 

 Two new methods of studjnng problems connected with the teeth, especially in 

 relation to their susceptibility to caries, have been adopted in the researches to be 

 described. 



