Literary Notices. 393 



which is at present under consideration, viz.: the second of the above mentioned 

 divisions — its component cells are found mainly in two positions: (a) in the lateral 

 horn proper, or in analogous positions above the level at which the lateral horn is 

 fully constituted; and (b) along the margin of that part of the gray matter which is 

 in immediate relationship to the formatio reticularis, and also among the strands of 

 the formatio reticularis itself. For convenience of description and reference these 

 may be distinguished as the apical cells and the reticular cells. The apical and 

 reticular cell systems have not a coextensive longitudinal distribution. 



The lateral horn is not fullv constituted above the lower half of the first thoracic 

 segment. This horn is not a transition from the lateral part of the anterior horn, 

 but a new and independent formation. It is represented in C. 8 and the upper part 

 of D. I by the outlying cells of the intermedio-lateral tract. The middle cells de- 

 scribed by Waldeyer do not form any part of the intermedio-lateral tract. The 

 number of cells in the intermedio-lateral tract is vastly greater than has hitherto 

 been recognized. The enumeration shows a total of 88,577 cells on the left side and 

 89,182 on the right. These figures are certainly below the total number. These 

 cells do not form a continuous column, but occur throughout the tract in groups or 

 clusters. These groups are not symmetrical on the two sides, although they 

 may present a general resemblance to each other. In each segment the cell groups 

 are arranged in a manner which may be regarded as characteristic of that segment. 

 The intermedio-lateral tract has a vascular supply largely independent of that of 

 the anterior cornu. The segmentation of the tract into groups or clusters or cells 

 is not due to the distribution of blood vessels or of the root fibers, but is probably 

 in some way related to their function. 



The researches of Gaskell and Langley as to the outflow of the sympathetic 

 fibers show that the distribution of these coincides in a remarkable manner with 

 the distribution of the cells of the intermedio-lateral tract. It is now certain that 

 the column of Clarke cannot be the source of origin of these fibers, and if there 

 is any spinal center at all it must, by exclusion, be either the "middle cells" of 

 Waldeyer or the intermedio-lateral tract, or both of these. This communication 

 shows that where there is the greatest outflow of sympathetic fibers there is the 

 greatest number of cells in the intermedio-lateral tract. The cervical sympathetic 

 gets its largest supply of fibers from the portion of the cord included between the 

 eighth cervical segment and the fifth or sixth thoracic segments — segments in which 

 the groups are most rich in cells. Then the outflow of the splanchnics is largest in 

 the lower thoracic region, and here again the number of cells markedly increases 

 and the character of the groups changes. The researches of Anderson and Her- 

 ring, and of Onuf and Collins, seem to point with considerable unanimity to the 

 intermedio-lateral tract as being the source of the sympathetic fibers. It must be 

 admitted, however, that other observers have found conflicting, and sometimes un- 

 intelligible, results of the experiment of section of the nerves, and further researches 

 are obviously needed. 



c. J. H. 



Holmes, J. S. The Biology of the Frog. New Tork, The Macmillan Company. 1906. Pp 

 1x370, 94 figs. $1.60. 



What Huxley did for the crayfish Holmes has done for the frog. 

 In this text-book for college students, which contains the materials of a course 

 of lectures delivered at the University of Michigan, the author has tried to present 



