Literary Notices. 469 



cephalon also contains several important new contributions. Of these, the most im- 

 portant is the sharp analysis which separates the centers of various other types of 

 somatic sensation from those for vision. In cyclostomes the tectum mesencephali 

 receives the lemniscus and, apparently, direct general cutaneous root fibers, besides 

 termini of the optic tracts. As we pass up the vertebrate series, the optic centers 

 become specialized away from the other somatic centers, the latter in higher fishes 

 appearing as a swelling in the lateral wall of the mesencephalon, the colliculus, and 

 in mammals as the colliculus inferior behind the tectum opticum. 



The final chapters on the evolution of the cerebral hemispheres are full of stimu- 

 lating suggestion. The series of diagrams of homologous centers and fibertracts in all 

 the types of fishes is impressive; still more so is the identification of the same struc- 

 tures in substantially the same relations save as modified by neomorphs in the brains 

 of the higher animals, including man. 



It is only in the discussion of the neo-pallium that we find much which might be 

 termed distinctively human neurology. In general, whatever iswell done in theother 

 text-books has been omitted by Johnston, so that this work will not supplant any 

 others, but rather serve as an introduction to their study. The great merit of the 

 book is its independence of tradition and authority. The brief bibliographies at 

 the ends of the chapters contain few titles save those connected with the newest 

 results of the functional school of neurologists. In fact, it is possible that the monoto- 

 nous repetition of the titles of a few American monographs throughout the book 

 will excite the derision of some critics. Still it must be remembered that there are 

 other general neurological bibliographies (one of the best of which we owe to John- 

 ston) and there was no need here for the citation of other originals than those from 

 which the motive of the work has been drawn. This independence, coupled with 

 the dogmatic form of statement fitting in a text-book, is responsible not only for the 

 greatest merit of the book, but also for its greatest defect. The delicate balancing of 

 probabilities on debatable points is of course out of place in an elementary text-book; 

 but the definite affirmation of well established fact and rather precarious hypothesis 

 in equally dogmatic form is at the best unfortunate and is usually unnecessary. 

 The somatic sensory character of the nervus terminalis, the theory of the paleostoma, 

 the homology of the direct cerebellar tract with the secondary vagus bundle (in 

 some places dogmatically asserted, though qualified in others) and the termination 

 of sensory trigeminus root fibers in the mesencepalon of mammals may be cited as 

 instances of over-zealous dogmatism which in my opinion mar the value of the book. 

 To some well-informed neurologists it may appear that a similar criticism should be 

 applied to the book as a whole. The author cuts his furrow across well cultivated 

 fields in so original a fashion that some may fear to follow him. To these it may be 

 replied in advance: First master the very recent literature of nerve components and 

 functional divisions of the brain in lower vertebrates; no just criticism of Johnston's 

 course is possible until the data which form his premises are thoroughly assimilated. 

 His method and chief conclusions will stand this test. 



There are a few unfortunate typographical errors. The most serious is the trans- 

 position of Fig. 175 with Fig. 177 and Fig. 176 with Fig. 178. If these cuts are trans- 

 posed as indicated, their descriptions will read correctly. On p. 158 the reference 

 line for the N. ophthal. prof, ends upon the R. ophth. super. VII . It should be 

 extended to reach the nerve immediately ventrad. On page 211 there is a lapse which 

 probably also belongs in the list of misprints. The sentence at the end of the first 



