214 WILLIAM H. F. ADDISON AND HAROLD W. HOW 



* 



spaced farther apart, the cytoplasm is drawn out and the cells are 

 very thin and flat. After breathing has begun, the mesenchjone 

 appears denser, with its nuclei more compacted, and the blood- 

 vessels are distended and more conspicuous. 



5. Measurements on cross-ruled millimeter paper show that the 

 lung tissue in sections of fetal lung of dog constitute 70 to 80 

 per cent of the entire area; in sections of lung of dog which has 

 breathed one hour, 40 to 60 per cent; and in sections of lung 

 of dog which has breathed two days, 20 to 30 per cent. 



LITERATURE CITED 



Ballantyne, J. W. 1902 Antenatal pathology and hygiene. William Wood, 



New York. 

 DE LA Croix, J. 1883 Die Entwickelung des Lungenepithels beim menschlichen 



Foetus und der einfluss der Atmung auf dasselbe. Archiv fiir mikros. 



Anatomic, Bd. 22. 

 DoHRN 1891 tjber den Alechanismus der Respiration des Neugeborenen. Ab- 

 stract in Archiv fiir Kinderheilkunde, Bd. 13. 

 Ferroni, E. 1899 Osservazioni e ricerche sui movimenti ritmici fetali intra- 



uterini. Annali di Ostetricia e Ginecologia, T. 21. 

 Flint, J. M. 1906 The development of the lung. Amer. Jour. Anat., vol. 6. 

 Geyl, a. 1880 Die Aetiologie der sogenannten 'puerperalen Infection' des 



Fotus und des neugeborenen. Archiv fur Gynakologie. Bd. 15. 

 Howell, W. H. 1911 . Text-book of physiology; 4th Edition. W. B. Saunders, 



Philadelphia. 

 KoLLiKER, A. 1902 Handbuch der Gewebelehre des Menschen. Bd. 3, p. 310. 



Edited by V. von Ebner. 

 Lecl.\rd 1815 Abstract in Intelligenzblatt of Deutsches Archiv fiir die Phy- 



siologie, Bd. 1, p. 154, under heading 'Untersuchungen, welche zu 



beweisen scheinen, dass der Fotus das Schafwasser athmet.' 

 Merkel, F. 1902 'Atmungsorgane,' in Bardeleben's Handbuch der Anatomie 



des Menschen. 

 Miller, W. S. 1893 The structure of the lung. Jour. Morph., vol. 8. 

 Preyer, W. 1885 Specielle physiologie des embryo. Leipzig. 



