SECTIONAL TRANSACTIONS.— I. 389 



dangerous, as shown by the examination with the lantern and spectral tests. In my 

 Card Test, also, the pattern is the same on every card, so that the examinee has to 

 judge by colour alone and cannot follow the design of the artist. 



An important point to note is that a test which is difficult to the normal-sighted i* 

 not necessarily difficult to the colour-blind. This is shown by the number of colour-blind 

 persons who can read Stilling's plates numbers nine and ten, the reading of which is 

 supposed to indicate very good colour perception. In fact, a test may be constructed 

 which can be read by the colour-blind but not by the normal-sighted. 



Afternoon. 

 Prof. R. J. S. McDowALL. — The Function of Carbon Dioxide. 



Prof. C. LovATT Evans, F.R.S., and Mrs. M. Grace Eggleton. — The 

 Removal of Lactic Acid after Exercise in the Mammal. 



Miss E. M. KiLLlCK. — The Adaptation of Small Animals to Carbon 

 Monoxide. 



Canaries and mice were exposed daily to atmospheres containing carbon 

 monoxide ; the concentration of CO varied in different experiments from 0-12 per 

 cent, to 0.26 per cent., and the exposure given varied in duration from 10 to 30 

 minutes. In all cases the animals used developed an adaptation to the gas, becoming 

 less affected with successive exposures. 



In the case of the canaries, the rate of absorption appeared unchanged during 

 adaptation, but there were indications that the red cell count in the blood increased ; 

 in the case of the mice, the results of two experiments suggested that with the appear- 

 ance of adaptation, the absorption of carbon monoxide was retarded. 



Friday, September 5. 



Dr. J. H. Shaxby. — The Weber-Fechner Law. 



Summary : — An attempt to formulate the general relation between Sensation and 

 Intensity of Stimulus on a statistical basis. It is shown that a chance distribution 

 of stimulus quanta among a finite number of sensory units in a receptor leads to the 



observed forms of the relations between -r^and S or log I. 



That log I and not I is the abscissa in the latter case is due to the mathematical 

 form of a frequency statistic, and not to any special physical or physiological 

 peculiarity of sense-organs. 



Prof. R. RuGGLES Gates. — The Blood Groups ayid their Inheritance. 



The blood groups are probably best represented by the formulae Oo^, A^, B/s, ABo. 

 They are inherited as fixed Mendelian units. There have been three views of their 

 inheritance ; (1) Two independent factors (Hirzfeld), (2) Three allelomorphic condi- 

 tions (Bernstein, Furuhata), (3) Two linked factors with 11 per cent, of crossing-over 

 (K. H. Bauer). The last view explains the cases which are exceptional. The agglu- 

 tinogens A and B probably arose as dominant mutations from 0. 



Among isolated peoples, the American Indians are mostly (a few A), the Eskimo, 

 Lapps and Australian natives being mostly O and A. Isolation will account for these 

 conditions if B originated as a mutation much later than A, since the highest propor- 

 tions of B occur in South and East Asia. If mutations from to A and B are still 

 occurring, they are probably of less frequency than 1 per cent. Such mutations, in 

 addition to wandering of races, may be necessary to account for the present condition. 

 Chimpanzees are mostly A (a few 0), platyrrhine monkeys and lemurs contain B. 

 Probably the human blood groups developed independently in man, through parallel 

 mutationfi. 



Discussion (Sections G, I) on Air Pressure Variations encountered in 

 Engineering Works, and their Physiological Effects. (See Section G.) 



