1878. ] Plaster of Paris as an Injecting Mass. 717 
Some of the specimens of A. americanum were remarkably 
large and fine, and might have been mistaken for di/atatum— 
with which form large specimens are no doubt often confounded 
—but a close examination revealed all of the characters that I 
have described as belonging to this species. 
=f 8 
PLASTER OF PARIS AS AN INJECTING MASS} 
BY SIMON H: GAGE, B.S. 
HE necessity for some artificial, colored medium to fill the 
blood vessels must have been felt by the first anatomists. 
Indeed, injections were rudely made by Eustachius and Varolius 
in the sixteenth century (Turner, 1, I, 812)? 
It was left, however, to De Graaf and Swammerdam to fairly 
initiate the process in the middle of the seventeenth century 
(Turner, 1, I, 812). 
De Graaf used mercury and colored fluids, and was the inventor 
of the injecting syringe (2, XVII, 291); but it is to Swammerdam 
that anatomists owe most, for he introduced the use of colored 
wax (2, XL, 477 and 1, I, 812). This answers fairly the require- 
ments of an injecting mass, as it may be used in the fluid state, 
but becomes solid very soon afterward. Upon renouncing anat- 
: omy for mysticism, Swammerdam gave his secret to Ruysch, his 
: fellow countryman (2, XL, 477), who perfected the art, and fairly 
approached in skill and excellence of results the refinements of 
modern anatomy (1, I, 812, and 2, XX XVII, 143). 
| About the middle of the eighteenth century, Monro primus 
4 published an essay on anatomical injections (4), in which were 
given very precise directions for the manipulation and preparation 
of the injecting mass. It was composed of wax, tallow, oil and 
turpentine, colored with vermilion, verdigris or lamp-black (3). 
In the latest works which treat of the technology of injections 
(5,6 and 7), nearly the same formule for injecting masses are 
given; and except a mere mention of gypsum in Martin (7, II, 
99), all coarse masses are solid at ordinary temperatures and must 
1 This paper is based upon investigations made in course of the eee of a 
Manual for the Dissection of Cats, Prof. Burt G. Wilder and the w 
? See list of works referred to at the end of this paper. The first Pais oe a 
the number on the list; the last, the page; the middle, Roman numeral, the volume. + - oe 
