and Laboratory Methods. 1543 



in a delicate membrane. The fibers in turn are made up of muscle elements 

 which cannot be further divided. The muscle elements arise in myogenous 

 cells, each cell producing several of the elements, though neither the fiber nor 

 the muscle column represents a single cell. In the LumbricidiT; the muscle col- 

 umns unite in well defined compartments, most pronounced in the longitudinal 

 series, each with distinct connective tissue membrane in which nuclei but no 

 cell boundaries are found. This connective tissue serves to reduce the pres- 

 sure and friction in muscular movement, and in limicolous species it forms a 

 compact layer beneath the peritoneum. The nuclei of the muscular tissue are 

 distinguished from those of the connective tissue by their larger size, and in 

 limicolous forms are often pedunculate and grouped along the lateral line. No 

 nerve runs along this line, though a fine canal, probably a lymphatic vessel, lies 

 among the nuclei cells. c. a. k. 



Sabin Dr. Florence R. An Atlas of the Me- ^^is atlas was prepared for the study 

 duUa and Mid-brain. A Laboratory Man- . 



ual. Pp. 123; 52 figs.; 8 pi., 1901. The of the human brain, and it will prove 

 Friedenwald Co., Baltimore. ^1.75. to be a valuable aid in the laboratory 



for the study of the brain of lower types. The abundant drawings of typical 

 sections, and above all the elegant colored plates of the medulla and mid-brain 

 regions, with their several parts shown in relief, will serve to elucidate these 

 difficult and complicated parts of the brain. It is stated that reproductions in 

 wax from the studio of Zeigler, in Freiburg, will be available witliin the year. 

 The material studied was preserved in Mliller's fluid and stained by the Wright- 

 Pal method. Sections of 70 jx thickness were made in a horizontal plane and 

 every other one used as the basis for reconstruction in wax by the Born method. 

 Wax plates two millimeters in thickness were used, thus giving a magnification 

 of 14.5. The wax was composed of 19 parts ordinary beeswax and 1 part resin. 

 To facilitate the counting of the sections in the model, every fifth plate was made 

 black by an admixture of lampblack. Melted wax of a weight sufficient to cast 

 a plate of the desired size is poured through a strainer into a tarred receptacle, 

 and then emptied upon a pan of hot water, bubbles being removed by a strong 

 gas flame. When firm, the plate is removed to a level surface to harden. The 

 drawings from the sections were made by the aid of a projection apparatus 

 and an electric lamp, the image being received upon a rigid but movable screen, 

 and care being taken to preserve a uniform magnification and orientation of the 

 sections. Drawings are then transferred to the wax plates by carbon paper, and 

 finished in oil paints. The sections thus outlined are cut from the plates, 

 which are slightly warmed, and placed upon a sheet of glass, a thin, narrow- 

 bladed knife being used for the cutting. The sections, and the shells also, are 

 then piled up in proper relation and their edges fused, thus giving a model of the 

 external form of the organ and a mould for a plaster cast of the same. The 

 different structures of the organs were then modeled separately, and the whole 

 so united as to display the true spatial relations of the various nuclei and fiber 

 tracts. The result, even as shown in the figures, will serve to elucidate and 

 simplify greatly the study and the demonstration of the structure of these im- 

 portant but very complex organs. c. a. k. 



