REVIEWS. 87 



fibres, small spaces occupied by connective tissue corpuscles, 

 and communicating more or less completely Avith each other, 

 being left between the bundles, and representing the lymph- 

 canalicular system. In guinea-pigs a meshwork of unstriped 

 muscle-fibre was also found, more especially developed in 

 those parts which move most freely in respiration, and show- 

 ing in the meshes lymphatic lacunae, which communicate 

 with the rich subpleural lymphatic plexus. The vessels 

 forming this arise in the superficial alveoli, receive branches 

 from the deeper parts of the lung, and discharge themselves 

 into trunks that run in the ligamenta pulmonis to the 

 bronchial glands. Dr. Klein has satisfied himself of the 

 existence of stomata forming a communication between the 

 cavity of the pleura and the above-mentioned superficial 

 lymphatic plexus and intermuscular lymph-spaces ; so that 

 when these stomata are dilated (as happens in inspiration) 

 the lymphatic system of the lung may become filled with 

 whatever matter may occupy the pleural cavity. The stomata 

 are best seen in the lungs of animals suffering from chronic 

 pleurisy, when their position becomes very clearly indicated 

 by a germination of the endothelium at their margins. 



Dr. Klein next describes the lymphatic system of the 

 bronchi. This consists of a rich network in the adventitia, 

 constituting the peribronchial lymphatics, which receive 

 branches from the submucous tissue, and anastomose with 

 the perivascular lymphatics which accompany the blood- 

 vessels. In the guinea-pig's lung (especially in animals 

 suffering from artificial tuberculosis) there are spherical, 

 oblong, or even cord-like accumulations of adenoid tissue in 

 the wall of many peribronchial lymphatics. The larger 

 ones are provided with a special network of capillary blood- 

 vessels. These were suspected by Burdon Sanderson, who 

 first described them, to be connected with the lymphatics, 

 and are shoAvn by Dr. Klein to be what he has called " peri- 

 lymphangeal follicles," consisting of adenoid tissue in direct 

 connection with the lymphatic wall. These follicles were also 

 found in the rabbit's lung, but less numerous and not 

 of so dense a structure. The rootlets of the peribronchial 

 lymphatics consist chiefly of a system of communicating spaces 

 in the mucosa, the muscularis^ and the submucosa, which 

 are interfascicular, and vary in size according to the amount 

 of separation of the contiguous bundles. They are smallest 

 in the mucosa, where they consist of lacunae and anastomosing 

 canals, whereas in the adventitia they are elongated or 

 rhombic spaces ; the former spaces are occupied by branched 

 connective-tissue-corpuscles, while the latter are lined by 



