1881.] ^^* [Wilder, 



psychological observations which are constantly making in all parts of the 

 world. But, with all deference to the presumed views of the many and 

 indefatigable workers in this finer field, I hold that the more urgent need 

 is for a provisional, at least, identification and nomenclature of the msihle 

 parts. 



I am loth to believe that the authors of some histological contributions 

 are not altogether clear upon the laosition and relations of the parts con- 

 cerned ; but I apprehend that many readers of such contributions fail to 

 appreciate their excellencies or to recognize their defects from the lack of 

 an adequate familiarity with the gross anatomy of the brain ; a lack which 

 seems almost unavoidable so long as the chief dependence is placed upon 

 the text-books, or upon the appearances presented by human brains in the 

 condition in which they commonly find their way to the dissecting-table. 



Had a recent writer employed the fresh or well-preserved brain of a cat 

 in place of the (presumably) distorted and semi-decomposed human organ, 

 he never could have published a paper "De la non-existence des trous de 

 Monro;" nor, indeed, does the acceptance of a paper with such a reac- 

 tionary title indicate that the editors of "Progres Medicale, Nos. 25, 26," 

 have left the beaten track in this respect. 



Whoever will carefully examine the- fresh or well-preserved brains of 

 cats need not, unless he prefer to accejjt authority in place of the evidence 

 of his eyes, either doubt the existence of the "Foramina of Monro," or 

 believe that these openings are primarily for the "transmission of the 

 choroid plexus." Neither need he believe that "the third ventricle com- 

 municates with the fifth" in anj^ animal, or at any period of develop- 

 ment ; that "the great transverse fissure " is a real cleft from the outside 

 of the brain into its "ventricular cavities ;" that the "corpora quadrigem- 

 ina, pineal body, corpora geniculata and thalami are internal parts of the 

 cerebrum ; " or that, in the cat at least, the thalami enter, in the slightest 

 degree, into the formation of "the floor of the lateral ventricles." 



With the view of aiding in the correction of some of such current mis- 

 apprehensions, and paving the way for more sound and enduring work 

 in other directions, the present paper is purely morphological, and all 

 teleological considerations have been excluded. 



Moreover, as has been said already, only a general view of the organ is 

 here given. Each part of the brain requires more or less extended mono- 

 graphic treatment. Not only should its average or usual form, structure, 

 and connections be determined, but its variations should be noted, and cor- 

 related with knoAvn difl:erences in respect to the age, sex, breed, color and 

 disposition. Anomalies also should be recorded. Of course, such striking 

 cases as the absence of the callosum, reported by the writer in 1879 {13) 

 would be at once remarked ; but in many other respects we are as yet un- 

 aware what is the real normal condition, and are hence unable to deter- 

 mine the extent of departure therefrom. The small size of the cat's brain 

 and the ease with which large numbers may be obtained and preserved, 

 render it peculiarly adapted for this line of enquiry. 



