Monthly, Microscopical! Histology of Minute Blood-vessels. 209 
the piece is to be carefully washed in alcohol, then soaked in abso- 
lute alcohol, and finally mounted in a solution of dried Canada 
balsam in chloroform or benzole. The treatment by oxalic acid, 
subsequently to the action of the carmine-borax solution, has the 
additional effect of altering the purplish-red colour, derived from 
that fluid, to the brilliant hue obtained by the use of the ammoniacal 
solution of carmine ordinarily employed in histology. The latter 
has the disadvantage of being apt to dissolve out the previously pro- 
duced silver staining, an annoyance completely avoided by the 
carmine-borax solution. 
Preparations carefully made by the above process closely re- 
semble the fresh tissues, as they appear after staining if immersed 
in glycerine or syrup: they are somewhat more transparent, but 
not inconyeniently 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. 
[It will be observed that we have omitted a great number of 
photographs, as woodcuts of them have not been published. | 
I. Sketch of a 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 pre- 
paration No. 3378, Microscopical Section. Magnified 400 diameters 
