Literary Notices 365 



ized types, which before were incapable of analysis. In other words, the phylogeny 

 should be read backward as well as forward. Only in this way can the study of 

 generalized types yield its best fruits. 



c . I . H . 



Van Gehuchten, A. La loi de Waller. Le Nevraxe,\-o\. j, iasc. 1. 1905. 



In this lecture, delivered at the University of Utrecht, Professor van Gehuch- 

 ten has summarized the recent experimental work on Waller's law, and sketched 

 the history of the conflict which has waged about the question of so-called retro- 

 grade degeneration. As is well known, he has studied exhaustively the phenomena 

 of central degeneration, which he finds sometimes to occur, though more tardily 

 than the degeneration of the peripheral portion of the nerve. This is not, however, 

 a cellulipetal process; it is initiated in the cell body. Van Gehuchten would 

 reformulate the law of Waller thus: When a central or peripheral nerve tract 

 is severed, the peripheral portion always degenerates. The behavior ot the cen- 

 tral portion depends upon the intensity of the reaction of the cells ot origin to the 

 lesion. If the lesion is not so severe as to cause the death of these cells, the fibers 

 of the central portion remain intact. Otherwise the atrophy of the cells of origin 

 induces the secondary degeneration of the central portion of the nerve. 



Van Gehuchten criticises the current conception of nervous degeneration. 

 It is not a process signalizing the death of the nerve. Quite the contrary, it is a 

 process of reorganization, a regulatory phenomenon. Even the destruction of the 

 axis cylinder and the fragmentation of the myelin take place only in an evniron- 

 ment of living tissue, and the proliferation of the nuclei of the sheath ot Schwann 

 is distinctly a step in regeneration, which may or may not come to anything, depend- 

 ing on the other conditions of the tissue. 



C.J. h. 



Maxwell, S. S. Chemical Stimulation of the Motor Areas of the Cerebral Hemispheres. Journal 

 Bio!. Chem., vol. 2, no. 3. 1906. 



We quote the author's summary: (i) Substances applied to the surface of 

 the cortex either give no indication of stimulation, or do so after so long an interval 

 that they would have time to act osmotically or by diffusion upon the underlying 

 white matter. (2) The white matter of the motor areas can be stimulated chem- 

 ically by the calcium precipitates and by barium chloride in solutions isosmotic 

 with the blood serum. The response to such stimulation is very prompt, occurring 

 within a few seconds at most, after application of the solution. The same sub- 

 stances when applied in the same concentration to the cortex give no result at all 

 or only after an interval of some minutes. (3) Solutions of high concentration 

 can stimulate the white matter by osmotic action very promptly and effectively. 

 (4) When solutions are injected into the gray matter but not so deeply as to reach 

 the white matter no evidence of stimulation is seen. The gray matter is apparently 

 devoid of irritability to chemical and osmotic stimulation as well as to mechanical 

 and electrical stimulation. 



Grasset, J. Demifous et demiresponsables. Paris, F. AUan. Pp. 297. 1907. 



In this work the author takes up the consideration of those individuals who are 

 not insane or mentally deficient in the ordinary sense of these terms. An attempt 



