286 REVIEW. 



to him, form a mesliwork in the crystalline cone cells, being derived 

 from an axial nerve-fibre, which runs up the rhabdora in order to 

 spread itself out in those cells. It certainly cannot be at once ad- 

 mitted that the fibres which Patten has thus traced in so many 

 directions are nerve fibres, though possibly they are so. On the 

 other hand, contrary to his assertions in reference to the Arthropod 

 eye. Patten lays down the law in a dogmatic fashion in regard to 

 the Molluscan hypodermis. " The nerves," he says, " must termi- 

 nate between the cells, and probably extend to their very outer 

 ends." The "must" of the foregoing assertion depends on the cor- 

 rectness of a speculative account of the phylogenetic development 

 of a nervous system, for many of the details of which Dr. Patten has 

 no conclusive grounds to urge. At present, it may be remarked, 

 histologists have been led, by the observations of Ranvier and others, 

 to admit that nerve-fibres do in some regions terminate between the 

 cells of the epidermis of Vertebrata, but it is also very generally 

 held that nerve-fibres of organs of special sense terminate in the 

 substance of special nerve-end cells. 



Dr. Patten's observations are possibly correct, but he does not 

 strengthen the confidence likely to be placed in them by dogmatism 

 of the kind in which he indulges. Our knowledge of the relation 

 of nerve-fibres to nerve-end cells is admittedly very unsatisfactory, 

 and will require observations over and above those of Dr. Patten 

 to put it on a satisfactory footing. 



Such being the main facts of importance which Dr. Patten seeks 

 to establish, we may pass to a brief notice of some of his more 

 astonishing theoretical statements. In the course of the extensive 

 memoir (over 200 pages) which Dr. Patten has devoted to this 

 subject, it is very seldom that we find a continuous straightforward 

 and intelligible account of the facts, with a sober discussion of pro- 

 babilities as to matters in which his own observations are in con- 

 flict with those of other observers, or are incomplete. Dr. Patten 

 is continually introducing into his record, with an unbecoming 

 assumption of wisdom and authority, speculations or statements of 

 a theoretical nature, which are so extravagant and betray so 

 much ignorance as to make the reader regret very heartily that 

 they have been allowed to disfigure a treatise which must on other 

 grounds command attention. For instance : — 1. On p. 625 the 

 description of the eye of Penseus is introduced with the follovping 

 utterance : — " The great impetus that modern zoological science 

 has received from comparative anatomy has not been due so much to 

 more subtle or able comparisons as to a more perfect knowledge of 

 the structure of single forms." How there is to be comparative 

 anatomy without comparison, or how comparison is to proceed 

 without an increased knowledge of the single forms compared, is not 

 explained by Dr. Patten. The sentence, so far as it means any- 

 thing, appears to be a negation of the value of scientific morphology 

 altogether. This, however, is a trifle compared with what followp, 



