lyo Literary Notices. 



Locy, William A, On a newly recognized Nerve connected with the Fore-brain of Selachians. Anat. 

 ^ns., Bd. 26, pp. 33-63,111-123. 1905. 



This paper describes the nerve, its ganglion and root, as found in twenty genera 

 and twenty-seven species of selachians, and its embryonic history in Squalus 

 acanthias. In the adult the nerve enters the dorsal surface of the brain in some 

 species; in others, it enters the ventral surface. In the embryo it is primarily con- 

 nected with the lamina terminalis. It is therefore called the nervus terminalis. 

 It precedes the olfactory nerve in development and probably arises from the gang- 

 lionic crest. It contains meduUated and nonmeduUated fibers and it distributed 

 to the olfactory epithelium. Its peripheral arrangement has certain resemblances 

 to branchial nerves. LocY considers the nerve homologous with the preoptic 

 ventral nerve of Protopterus and Amia. 



G. E. c. 



de Vries, E. Over het Ganglion Vomeronasale. Koninklijke Akademie van IVetenschappen te 

 Amsterdam, Afdeeling van 22 April, 1905. (Also, Note on the Ganglion Vomeronasale, 

 Ihid., Proceedings of the Section of Sciences, Vol. 7, Part 2, July, 1905.) 



Demonstration in the human embryo of a dorsal olfactory nerve in addition to 

 the ventral well-known olfactory nerve. The new nerve connects with the ganglion 

 vomeronasale and Jacobson's organ and is regarded as related to Locy's new 

 nervus terminalis of selachians. c. j. H. 



Norris, H. W. The so-called Dorsotrachealis Branch of the Seventh Cranial Nerve in Amphiuma. 

 Proc. Iowa Acad. Sri., Vol. 11, 95-102. 1904. 



A description of the nerve from serial sections, with especial reference to Kings- 

 ley's recent work on the cranial nerves of Amphiuma (Tufts College StuJies, 

 1902). G. E. C. 



Mathews, A. P. The Nature of Chemical and Electrical Stim\ilation. I. The Physiological Action 

 of an Ion Depends upon Its E'ectrical State and Its Electrical Stability. Amer. Jour. Physiol., 

 Vol. XI, pp. 455-496. 1904. 



The results of Mathew's important study of the nature of stimulation can best 

 be stated by means of quotations from his summary. 



1. The stimulation of the sciatic nerve of the frog, which is produced by 

 nearly all electrolytes and nonelectrolytes having an osmotic pressure of about 

 fourteen atmospheres, "is probably due to the extraction of water setting up a 

 definite change in the colloids of the nerve, rendering the protoplasmic hydrosol 

 unstable." 



2. Electrolytes which are too dilute to extract water act through the electrical 

 condition of the solution. "All anions have a stimulating action; all cations a 

 depressing action." 



3. "The physiological action of any ion depends (i) on its concentration; 

 (2) on the sign of its electrical charge; (3) on its electrical stability or ionic poten- 

 tial. Its action is also modified by its velocity and weight; the faster it moves the 

 more powerful it is; the heavier it is, the less powerful." 



4. "Physiological action is hence dependent upon the electrical state and 

 stability of the ion and is independent of chemical composition, except as the 

 chemical composition may influence its velocity and weight." 



5. Whether any salt stimulates or depresses, depends upon the relative effi- 

 ciency of its anion and cation. If the anion markedly predominates, as in hydrates, 

 the salt stimulates; if the cation predominates, the salt depresses. 



