'240 IXFLUKNCE OF COOLIXG POWERS OF ATMOSPREIJE. 



dift'ereuce in the gain in weight between the cool and the warm 

 })eriods. September to January is the autumn-winter period in 

 Jioiston. It is seen that during this period the gain in weight is 

 four times more raj^id, on an average, than during the period 

 February to June. 



I ha.ve for some time been conducting experiments on the 

 rate of increase of weight of young animals, especially puiJS, under 

 various, conditions of cooling. Pups from the same litter are 

 kept in cages placed («) in a warm engine-room,- (&) in a room 

 kept artificially cool by fans and ice, (c) in an ordinaiy room. 

 Kata thermometer readings are taken three times a day in each 

 room, and the weight of the animals is recorded daily. These 

 experiments have not yet proceeded very far, but it is ajready 

 very evident that the most rapid increase in weight takes place 

 hi pui>s exposed to the Jiighest cooling powers. 



The tables in this paper have already appeared in a state- 

 ment o£ the ventilation problems of Johannesburg.'^ I venture 

 to place them before you in the hope that further information as. 

 to the influence of cooling power on growth may be revealed. In 

 particular, I have found it very difficult to obtam reliable records 

 of the growth of infants in warm and cold seasons, in spite of 

 much correspondence on the matter. 



Eeferexces. 



1 Medical Eesearcli Committee: Report on the Present State of Knowledge 

 concerning Food Factors (Vitamines) . 



- Cluver : S. African Geographical Journ., Vol. III.. No. 1, 1919. 



'•' Hill : The Science of Open Air Treatment, Vol. I. Special Report Seiie? 

 No. .32, Medical Research Council. 



■' Hill and Campbell : Brit. Med. Journ , March 11, 1922. 



•'Porter: American Journal of Physiology, Vol. LII, No. 1. 



•^ Cluver : Medical Journal of South Africa, April, 1922. 



