315 



separation of the fringes is found to vary with the distance of the 

 edges from each other horizontally, or in the direction of the rays. 



2. " Researches on the distribution of the Blood-vessels, &c. in 

 the Lungs." By James Newton Heale, M,D. Communicated by 

 J. Hodgson, Esq., F.R.S. Received May 20, 1853. 



After referring to the discrepancies in the opinions entertained 

 by anatomical writers both with respect to the distribution and to 

 the functions of the blood-vessels with which the lungs are supplied, 

 the author states the leading features in which the observations made 

 by him differ from those which have hitherto been published. He 

 finds that : — 



1st. The pulmonary artery makes no anastomosis whatever with 

 any other artery, nor do its own branches anastomose together ; its 

 branches go direct to the air-cells, and are there distributed, and ter- 

 minate as arteries ; none of its branches go to any other tissues of 

 the lungs besides the air-cells, except some few which perforate the 

 sub-pleural cellular tissue, and are distributed to the pleura ; some of 

 these also cross the posterior mediastinum beneath the pleura, and 

 reach the thoracic pleura. 



-2ndly. The bronchial (so called) arteries have their own special 

 distribution, which will be described further on ; they do not supply, 

 in the smallest degree, any portion of the bronchial mucous membrane, 

 and they form no sort of communication, either with the pulmonary 

 arteries or veins, except as supplying their cellular sheaths, and 

 therefore in all probability furnishing their vasa vasorum. 



3rdly. The bronchial mucous membrane is very freely supplied 

 with an exceedingly vascular plexus, of a peculiar and very charac- 

 teristic description, which is found to ramify in every part of the 

 bronchial membrane, and which may be traced even as high as the 

 trachea. The whole of this plexus is derived from the air-cells, and 

 terminates ultimately by means of minute radicles, which form trunks 

 and join the pulmonary veins. No trace whatever of any branches 

 of the pulmonary artery, previous to this becoming capillary in the 

 air-cells, is found in any part of the bronchial membrane. 



4thly. The blood being brought to the air-cells by means of the 

 pulmonary artery, is wholly returned by the pulmonary veins ; but 

 the trunks of these latter are form^ed by the junction of two distinct 

 sets of radicles, namely, one set which comprises those which are 

 formed from the perimeters of the air-cells {i. e. that part of the 

 air-cell which is distant from the bronchial tube to which it is 

 connected), and which at once form trunks which are visible on the 

 surface of the lungs, and of all the lobules, and especially of the 

 surfaces which adjoin the interlobular fissures ; the other set consist 

 of those which are derived from the bases of the air-cells, and which 

 supply the bronchial membrane, and then terminate by radicles form- 

 ing trunks, which join the before-mentioned set of pulmonary veins ; 

 and from these conjoined, the larger venous trunks are derived, which 

 at length accompany the larger bronchi, and the pulmonary arteries, 

 and which finally terminate in the left auricle of the heart ; so that 



