88 GLANDS. 



the common cavity. But this latter, instead of being 

 a large empty space in the centre of the lobule, such 

 as we see in the frog's lung, forms a sort of corpus 

 cavernosum, or cavernous sinus, by the anastomosis of 

 numerous trabeculce which traverse its interior, and 

 which are given off from the walls of the vesicles. 



I am of opinion, however, that all of the lobules 

 of the lung are not constructed exactly after this 

 model; some of them seem to be mere diverticula 

 from the bronchial walls, presenting vesicular depres- 

 sions upon their internal surfaces, but without the 

 trabeculce, resembling, in short, more perfectly, the 

 lung of the frog. We can often detect lateral open- 

 ings near the summit of a lobule, by means of which 

 it communicates with neighboring lobules ; but the 

 number of these orifices is limited.* 



* In a monograph published within the present year (The Anatomy of 

 the Human Lung, an Essay for which was awarded the Fothergillian 

 gold medal of the Medical Society of London, by A. T. HOUGHTON WA- 

 TEES, Lecturer on Anatomy, &c., &c., Liverpool. Lond., 1860), contain- 

 ing the results of a considerable amount of original research, the true 

 respiratory structure of the lung is somewhat differently described. The 

 trabeculce, forming by their anastomoses a species of corpus cavernosum 

 in the common cavity of the primary lobules, are not recognised. The 

 following quotations, slightly condensed from the author's own language, 

 give the result of his investigations. In regard to preparations, he says 

 (p. 168) : u The plan I have adopted, and which I believe affords the best 

 means for investigating the lung tissue, consists in the injection of a 

 colored solution of gelatine into the blood-vessels, inflation of the air- 

 tubes, and gradual desiccation. In my first attempt I inflated the air- 

 tubes before injection of the blood-vessels, but I afterwards injected 

 before inflation. The colors I have used have been red, yellow, and 

 blue. The red, a finely powdered vermilion ; the yellow, a chromate of 

 lead, formed, at the time, by the decomposition of acetate of lead by 

 bichromate of potash ; the blue, a Prussian blue, formed by the decom- 

 position of ferro-cyanide of potassium and sesquichloride of iron. When 



