CAPILLARIES OF LUNGS. 



749 



Fig. 402. 



Blood is exposed to the Air on both sides. It has been calcu- 

 lated that the number of these Air-cells grouped around the 

 termination of each air-tube in Man is not less than 18,000 ; 

 and that the total number in the entire Lungs is six hundred 

 millions. 



584. The following list of the parts of the bodies of Vertebrata, 



of which Injected 

 preparations are 

 most interesting as 

 Microscopic objects, 

 may be of service 

 to those who may 

 be inclined to apply 

 themselves to their 

 production. — Ali- 

 mentary Canal ; 

 Stomach, showing 

 the orifices of the 

 Gastric Follicles, 

 and the rudimen- 

 tary Villi near the 

 pylorus ; Small In- 

 testine, showing the 

 Villi and the orifices 

 of the Follicles of 

 Lieberkuhn, and at 

 its lower part the 

 Peyerian glands ; Large Intestine, showing the various Glandular 

 follicles: — Respiratory Organs; Lungs of Mammals, Birds, and 

 Reptiles; Gills and Swimming-bladder of Fish: — Glandular 

 Organs; Liver, Gall-bladder, Kidney, Parotid: — Generative 

 Organs ; Ovary of Toad ; Oviduct of Bird and Frog ; Mammalian 

 Placenta ; Uterine and Foetal Cotyledons of Ruminants: — Organs 

 of Sense; Retina, Iris, Choroid, and Ciliary processes of Eye, 

 Pupillary Membrane of Foetus; Papilla? of Tongue; Mucous mem- 

 brane of Nose, Papillae of Skin of finger: — Tegumentary Organs; 

 Skin of diiferent parts, hairy and smooth, with vertical sections 

 showing the vessels of the Hair-follicles, Sebaceous glands, and 

 Papilla? ; Matrix of nails, hoofs, &c. : — Tissues; Fibrous, Muscular, 

 Adipose, Sheath of Tendon: — Nervous Centres; Sections of Brain 

 and Spinal Cord. 



Arrangement of the Capillaries on the walls of 

 the Air-cells of the Human Lang. 



The study of the Embryonic Development of Vertebrated 

 animals has been pursued of late years with great zeal and 

 success by the assistance of the Microscope ; but as this is a 

 department of inquiry which needs for its successful pursuit a 

 thoroughly -scientific culture, and is only likely to be taken-up by a 



