264 Drs. Lochhead and Cramer. Glycogenic Changes [Jan. 1, 
placente of sheep and cows. He did, however, find it in the flattened or 
papilliform bodies with which the umbilical cord and the internal surface of: 
the amnion are covered, the quantity increasing up to mid-term and then 
decreasing. 
Lately Jenkinson* has again investigated sheep’s placente histologically 
and found glycogen in the uterine epithelium and trophoblast of the extra- 
cotyledonary region; there was none apparently in the maternal cotyledons 
and none in the villi. 
The time of origin of the glycogenic function of the liver has long been a 
subject of controversy. While Bernard} and Barfurtht concluded from their 
investigations that the liver first functioned as a glycogen-secreting organ 
about the middle of intra-uterine life, Pfltiger§ proved by means of his more 
reliable method that small quantities of glycogen are present in the liver at 
much earlier stages. According to this author, the fcetal liver shows the 
same behaviour with regard to its glycogenic function as the adult liver, and 
since his material was obtained from the slaughter-house, he ascribed the 
small amount of glycogen found in the feetal liver to the imperfect feeding of 
the mother animals before they are slaughtered. 
The recent work of Lubarsch|| Gierke, Adamotf,;** and especially the 
detailed chemical investigation of Mendel and Leavenworth,tft have proved 
that foetal tissues are not so rich in glycogen as adult tissues, as was believed 
formerly. While the earlier observers concluded from their observations that 
glycogen was an essential constituent of tissues in which a rapid cell forma- 
tion and cell development take place, the later authors deny that there is any 
relation between the energy of growth of embryonic tissues and their glycogen 
metabolism. 
The present investigation is an attempt to throw light on the part played 
by glycogen in the development of the foetus by means of a systematic 
investigation on the glycogenic changes in an age-series of foetal animals. 
Methods. 
‘For this investigation rabbits were used. The animals were kept in the 
laboratory, and the date of insemination was noted in each case. In this way 
-* Jenkinson, ‘ Proceedings Zoological Soc. of London,’ vol. 1, 1906. 
' + Bernard, ‘ Journal de la Physiologie de 1Homme, vol. 2, 1859, p. 335. 
+ Barfurth, ‘Archiv fiir Mikroskopische Anatomie,’ vol, 25, 1885, p. 529. 
§ Pfliiger, ‘ Pfliiger’s Archiv,’ vol. 102, 1904, p. 305. 
|| Lubarsch, ‘ Archiv fiir Pathologische Anatomie,’ vol. 183, 1906, p. 192. 
. (| Gierke, ‘Glycogen in der Morphologie des Zellstoffwechsels,’ Habilitationsschrift. 
. Freiburg, 1905. 
** Adamoff, ‘Zeitschrift fiir Biologie,’ vol. 46, 1905, p. 281. 
++ Mendel and Leavenworth, ‘ American Journal of Physiology,’ vol. 20, 1907, p. 107. 
