2 2 Journal of Comparative Neurology. 



is a real corpus quadrigeminum, yet we trust that everyone who 

 will take the trouble to carefully look through series of sections of 

 fish brains will recognize at least the resemblance of structure 

 and similarity of position. While the employment of such terms 

 as frontal lobe, occipital lobe, etc., in the previous instalment 

 was with the definite understanding that these expressions were 

 descriptive and not intended to express homologies, in the pres- 

 ent case it is generally proving possible to use terms for organs 

 which are regarded either as rather strict homologies of those in 

 man or equivalent in some true sense. Of course such struct- 

 ures in the human brain as are recognized by virtue of their 

 external configuration only can have no homologues in fishes. 



Considerable time has been devoted to the search for metli- 

 ods better adapted for the purpose of this work, but thus far 

 nothing has given as satisfactory results as the chromacetic solu 

 tion recommended above. For certain purposes the staining 

 with acid fuchsin after or with hematoxylin seems advisable, as 

 it assists in differentiating the connective elements. As an ad 

 hesive, a solution of photoxylin in chloroform seems to promise 

 well, but a mixture of egg albumen and 2 — 3 parts of glycerine 

 does not discolor so much as to seriously affect the usefulness of 

 the sections, much as it interferes with the beauty of the slides. 

 (In giving the fusing point of the paraffin employed, p. 338, 

 above, "50 deg. C." should be substituted for "30 deg C.'') A 

 method which promises well for the treatment of ribbon sections 

 is to float the bands out upon warm water somewhat below the 

 fusing point of the paraffin. After cutting to the desired length 

 the bands are lifted out on the prepared slide and allowed to dry 

 before the paraffin is fused. Much care is required, but if suc- 

 cessful, the wrinkles which destroy the usefulness of very thin 

 ribbon sections may apparently be thus avoided. 



The complicated character of the subject and the difficulties 

 of a lucid treatment must not be underestimated. The effort to 

 combine the scattering descriptions of previous writers warns 

 the author that he cannot hope to escape obscurity and diffuse- 

 ness. Headings are prefixed which may aid somewhat in finding 

 what is desired and an index of terms at the close may assist in 

 comparing our results with those of the pioneer authors, though 

 absolute uniformity has not been attained. 



