CHANGES DURING PREGNANCY 543 



ninth month. In guinea-pigs the fu-tal liver contains considerable 

 amounts of fat, especially towards the end of gestation. 1 This excess 

 of fat, which is less saturated than connective tissue fat. disapj>ears 

 during the first two or three days after birth. 



(ft.) Oriijin <>/'?/<> F-tl Fl. As to its origin, Thiemicl i - 

 that it is not derived from the alimentary fat of the mother, since 

 after feeding a dog in two successive pregnancies on widely diHerent 

 t'ats. parmin and linseed oil, he could determine no difference in the 

 constitution of the fcptal fat. Oshima 3 comes to the same conclusion 

 from his investigations on the number of ultra-microscopic particles 

 in the blood of cats, rabbits, and guinea-pigs. He states that the 

 number is dependent on the stage of development, and indej>endent 

 of the condition of the mother's blood for example, when a great 

 increase is produced by rich fat-feeding. Capaldi, on the other hand, 

 states that the percentage 'of fat is the same in the maternal and 

 tVetal blood, at least at the end of pregnancy. Some feeding experi- 

 ments carried out by Hofbauer 4 agree with this. He administered 

 coco-nut oil, which consists essentially of the triglycerides of lanrinic 

 and inyristinic acids with a very small quantity of tripalmitin, n. 

 three pregnant guinea-pigs, and demonstrated laurinic acid in con- 

 siderable amount in the foetuses. Hence the fat of the food, or at 

 least one of its fatty acids, had been transmitted across the placenta. 

 But any conclusions based on the introduction of a foreign fat must 

 be guarded. 



In the foetus, fat is present in many of the tissues in a state of 

 tine division. Its widespread distribution and its amount, probably 

 equal at least to that of glycogen, are a characteristic of fo-tal life; 

 but its significance is not obvious if, as Bohr states, it is not a source 

 of energy. Guillot 5 showed that it did become a source nf energy 

 immediately after birth, when the fo'tus is faced suddenly with 

 the necessity to maintain its Inxly temperature against a lower 

 external temperature. The rapid disappearance of fat from the 

 foetal liver, observed by Imrie immediately after birth, also suggests 

 such an explanation, although Imrie himself suggests that the fat in 

 the fcetal liver is destined for the connective tissue depots. He found 

 twelve per cent, of fat in the lungs of f<Kuses dying during labour, 

 and only six per cent, after several hours' respiration. Fat may have 



1 Imrie and (iraham, "The Fat Content 'of Embryonir Livers," ./,: H><>l. 

 Clu-in., vol. xliv., 1920. 



- Thiemich, " Ueber die Herkunft des fiitalen Fettt-s, ' r, /,-,///,/. f. /'////.., 

 vol. xii., 18W. 



:! Oshima, " I'eber da.s Vorkommen von ultra-mikroseopischen Teilchen ini 

 fotalen Blute," <:-,,f ,/!,/. f. /'/,>/.<., vol. .\\i., 1907. 



4 Hofbauer, Biologie aer mentcMiche* /'/>>:. f<>. Wieii and I^ip/.ig, I'.wir,. 



"' (4uillot, quoted in Richet's IH'-tinnn"!,-" ! /'/-//x /.,/-//'- . Arti--K- " Fn-tn-." 



