384 



the disadvantage of being apt to dissolve out the previously- 

 produced silver staining, an annoyance completely avoided by 

 the carmine-borax solution. 



Preparations carefully made by the above process closely 

 resemble the fresh tissues, as they appear after staining if 

 immersed in glycerine or syrup ; they are somewhat more 

 transparent, but not inconveniently so, and possess the great 

 advantage of keeping unchanged for an indefinite period of 

 time. 



After these preliminary remarks, I proceed at once to the 

 description of the photographs.^ 



1. Photograph representing several venous radicles uniting 

 to form a small vein in the muscular coat of the urinary 

 bladder of the frog. Negative No. 102, New Series. From 

 preparation No. 3378, Microscopical Section. Magnified 

 400 diameters by Wales's ^th objective, illuminated by the 

 magnesium lamp. The preparation was made by Dr. J. C. 

 W. Kennon. 



The principal venous trunk represented in this photograph 

 is l-400th of an inch in diameter. It is formed by the union 

 of three smaller radicles, of which that on the left hand is 

 much out of focus. Another smaller radicle, also much out 

 of focus, joins the trunk on the left, near the bottom of the 

 picture. The walls of the venous trunk, and of those of its 

 branches which are in focus, are plainly seen to be formed of 

 somewhat irregular epithelial cells, which vary in shape and 

 size, averaging l-500th of an inch in length, and 1 -2200th in 

 breadth. The boundary of each cell is indicated by a zigzag 

 black line. In each of the cells which is accurately in focus, 

 a smooth oval nucleus, l-2800th of an inch in length, is 

 visible. In examining the original preparation, by changes 

 in the fine adjustment of the microscope, similar nuclei can 

 be seen in each of the epithelial cells. These nuclei, being 

 brilliantly stained with carmine, contrast sharply with the 

 black cell-boundaries resvdting from the silver imbibition. 

 By a still further alteration of the fine adjustment, the cells 

 and nuclei of the opposite side of the vein are brought into 

 view. 



In the tissue external to the vein, two kinds of nuclei are 

 shown in the photograph. The first are narrow and elongated, 

 averaging about l-i500th of an inch in length, and l-9000th 

 in breadth. These are the nuclei of the fibre-cells of the 

 muscular coat of the bladder. The fibre-cells themselves are 



' Copies of these photographs have been kindly sent to the Editors of 

 this Journal by Colonel Woodward. They will be forwarded for inspection 

 to any microscopical society or club making application. 



