64 THE LUNGS, BY FRANZ EILHARD SCHULZE. 



contents no longer visible, whilst the previously sharply-defined 

 nucleus has become very pale. 



In the alveoli of older animals,* the polygonal or irregularly 

 spheroidal epithelial cells, with their granular contents and 

 clear round nuclei, appear to be quite isolated, or arranged in 

 small groups of two or four (seldom more) between large trans- 

 parent thin structureless plates, either irregularly angular in 

 form, or with sinuous outlines, which originate in the further 



Fig. 132. 



Fig. 132. The bottom of an alveolus, as shown in a section made 

 parallel to the pleura from the lung of a Child injected with solution 

 of nitrate of silver. The Child had been born at the eighth month, 

 and had lived two days. Magnified 500 diameters. 



development in quite young animals, and with the above-men- 

 tioned changes, of the epithelial cells of the original structure, 

 and probably by the pressure of the rising capillaries, and the 

 tension of the enlarging alveoli ; perhaps also, as Elenz main- 



* I have employed the Cat, Dog, Rabbit, and Calf as subjects of inves- 

 tigation. The thick pleura, and the impossibility of obtaining the lungs 

 of Man sufficiently fresh, seriously interfere in his case with the treatment 

 by means of silver. 



