432 EDWARD HORNE CRAIGIE 



this distinction. Kadyi's nomenclature for the vessels on the 

 surface of the cord has been adopted by succeeding workers. 



Hoche, whose study is comparative, agrees fairly well with 

 his predecessors. He finds that the difference in the capillary 

 supply of the gray and white matter is much less in the rabbit 

 than in the dog, where the ratio is about 2 or 3 to 1. 



The most extensive comparative and embryological investi- 

 gation of the blood supply of the spinal cord is that of Sterzi 

 ('04), who describes it in all groups of vertebrates, from the 

 cyclostomes up, and shows how the vascularization improves as 

 one passes up the series. In studying the horse, he notes that 

 the capillaries of a single mesh in the gray matter twist greatly, 

 and that they are smaller at the head of the ventral columns, 

 where the mesh also is closer. The capillaries of the white matter 

 he finds to be larger than those of the gray matter, with which 

 they communicate. 



There is a good description of the vessels in the medulla 

 oblongata due to Adamkiewicz ('90), while those of the midbrain 

 have been studied by Alezais et D'Astros ('92) and by Shimamura 



('94). 



The arteries on the surface of the brain have been described 

 repeatedly, the paper of Hofmann ('00) being of particular 

 interest from the comparative standpoint. The comparative 

 anatomy of the circle of Willis and its main branches in the 

 mammalia has been well worked over by Tandler ('99, '02), to 

 whose observations some interesting additions were made by 

 Beddard ('04). These vessels were also the subject of an ex- 

 tensive phylogenetic, ontogenetic, and teratological study by 

 De Vriese, which appeared soon afterward ('05). 



The distribution of the vessels within the brain substance 

 has also been described by several authors since those already 

 mentioned. The most important of these are Beevor ('09) and 

 Stopford ('16). The former made a thorough and exact study 

 of the source of the blood supply of each part of the forebrain 

 in the human subject, while the latter made a similar investi- 

 gation of the pons and medulla oblongata. The only paper of 

 particular interest from the point of view of the present study 



