SECT. 4] HEAT-PRODUCTION OF THE EMBRYO 



735 



but the others equate well with those of Magnus-Levy, and form the 

 basis of our knowledge of the process. The gradual rise of heat- 

 production during pregnancy is particularly well shown in the figure 

 of Root & Root, reproduced here as Fig. 163. From the 6th month 

 it steadily rises until, at 6 weeks before birth, it is 23 per cent, higher 

 than at 4 months. The total increase in weight, however, was only 

 14 per cent., and a non-pregnant woman showing a similar increase 



Fig. 163. 



in weight would only have increased her heat-production by 5 per 

 cent., according to the tables of Harris & Benedict or Aub & Dubois. 

 Similar results were obtained by Sandiford & Wheeler. Murlin & 

 Carpenter had shown in 1 9 1 1 that if the energy exchange of a preg- 

 nant woman at the gth month were compared with the energy 

 exchange of the mother post partum, the metabolism total in each 

 case was exactly the same except for a balance of 4 per cent, in 

 favour of the pregnant woman. This means that there is no de- 

 flection in the energy consumption curve at birth, that the maternal 

 organism and the foetus function as two separate units in their 

 consumption of energy, arid that the rise of heat production during 



