ON THE PRENATAL AND NEONATAL LUNG 



WILLIAM H. F. ADDISOX AND HAROLD W\ HOW 



The Anatomical Laboratory of (he University of Pennsylvania 



EIGHT FIGURES 



IXTRODUCTIOX 



Of the various changes occurring in the lung at birth, we have 

 studied especially the increase in size of the spaces within the 

 respiratory lobules, and the change in the character of the con- 

 tents of these spaces. Whenever this portion of the lung's his- 

 tory is considered, the statement is made that, with the first 

 pulmonary inspirations after birth, the spaces become distended, 

 but we have found no data expressing the amount of this dis- 

 tention. As to the question of the existence of fluid contents in 

 the spaces of the prenatal lung, it is seldom mentioned in current 

 literature, although it would seem to be of importance, especially 

 in connection with the beginning of breathing. 



In making comparisons, we have used material from experi- 

 mentally controlled animals, in order to obtain specimens of pre- 

 natal and neonatal lungs, which would be comparable in all 

 respects. This was done by using animals of the same litter, 

 of which some had breathed, and others had not breathed. 



LITERATURE 



Measurements made on the minute parts of the lung have 

 been recorded by a comparatively small number of investigators. 

 Friedrich Merkel, in Bardeleben's Handbuch ('02), reproduces 

 from Rossignol ('46) a table of sizes of lung alveoli at different 

 ages. The first item in the list gives the mean size of alveoli 

 of newborn children which have not breathed, or have breathed 



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