8o Journal of Comparative Neurology. 



jection and of inspection by careful dissection or gross sec- 

 tioning. 



A brief resume of the results of these investigations is as fol- 

 lows : Key and Retzius found the metapore present in 98 out of 

 100 cases examined. In one of the exceptions there was a contin- 

 uous tela. They also found the lateral recesses open in all but 

 three. In two brains it was closed on both sides and in one 

 brain on one side. C. Hess examined the brains of 30 adults, 

 10 new-born children and 7 embryos of different stages, and 

 found the metapore absent in one. In 54 lateral recesses he 

 found all open except two. Others who do not give the num- 

 ber of brains investigated and who found the metapore present 

 are, Wilder, Morton, Kohlmann, Jacobi and others, and its pres- 

 ence is conceded in most of the descriptive anatomies. 



On the other hand, Kolliker states that the cavity is origin- 

 ally closed and always remains so, and Reichert that both the 

 metapore and foramina of Luschka are artifacts. Its presence 

 is questioned by Cruveilhier and See. The openings in the lat- 

 eral recesses, first discovered by Luschka, have been most fully 

 described by Key and Retzius, and later by Retzius, by Hess 

 and by Mihalkovics. Their presence is doubted by Wilder. 



In the lower animals most observers agree that the meta- 

 pore is absent but that the lateral recesses are open. Wilder 

 has found the metapore in the chimpanzee, baboon and several 

 old world monkeys. Hess found openings in the roof of the 

 ventricle of an embryo cat. Jacobi has proved the presence of 

 openings of the lateral recesses in the live dog by injecting 

 methyl blue into the subarachnoid cavity in the lumbar region 

 and having it emerge from a cannula placed in the ventricle of 

 the brain and vice versa. 



In the last year articles on the metapore and the foramina 

 of Luschka have appeared by A. Cannieu. His investigations 

 were partially by gross methods and partially histological. By 

 gross methods he found the metapore present in the dog, cat, 

 rabbit, guinea-pig, horse, ox, ass, and in man. He allowed 

 the brains of the lower animals to soften so that they would ap- 

 proximate the condition in which it is usual to obtain human 



