1892. | Briefer Articles. 127 
determination an investigation of their minute structure was under- 
"4 nder a low magnification a ma- 
ture spine presents the appearance repre- 
sented in fig. 1.. Barbs of various sizes 
and, for the most part, uniform in shape 
are disposed irregularly over its surface, 
being more numerous and larger near the 
point, the tip of which is well supplied 
with them. The interior tissue of the 
spine (fig. 3) is made up wholly of very 
thick-walled cells, the thickening in many 
cases being of such an extent as to en- 
tirely obliterate the cavity. From the 
ase to near the point of the spine 
throughout this tissue occur air cavities 
of different lengths but of nearly uniform 
: width (fig. 1, 2). 
of Gch ‘ribuloides; some: When examined under a higher mag- 
thespine, z,endof the spine more nification the true nature of the spine 
pee ne Dar, makes its appearance (fig. 2). Each barb 
's seen to have within it a cavity termin- 
ating, ‘ 
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poe 
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he cav 
» In the mature barb, with the 
Mterar : ; 
nor tissue. Neither does there ap- 
i j .— Cross tion of spine: 
S€quent] ae nay be ejected. Con- é peor Se tah it oF cavity. 
for the ¥ they would escape slowly— ooze out — which would account 
Prolonged irritation of the wound.—E.E. Gav, Lieut.U.S. A. 
