260 
BAIILOW ON TENDINOUS STRUCTURES. 
ing to account for the property, which the horse so remarkably pos- 
sesses of resting without necessarily seeking the recumbent 
posture. 
Mr. Mayhew’s remarks on the way in which he accounts for the 
obviation of traction, and its fatiguing effects, from the extensors of 
the fore* leg during a recumbent posture, are judicious, and go to 
shew that the flexion and extension of one joint are dependent, 
as just stated, upon corresponding actions taking place in other 
articulations of the same limb. I am inclined to believe that 
a certain elongation (limited it may be) of muscle is permitted 
without inducing fatigue. Although muscles possess the power of 
active contraction, they do not appear to possess that of active 
elongation. When the flexors of a limb have ceased to act, their 
subsequent power of elongation seems to depend not upon them- 
selves, but upon their antagonists the extensors, and vice versa. 
It is difficult to say how far this lengthening in either case may or 
may not be carried ; but nature would hardly, we think, so consti- 
tute an important tissue, destined for performing actions requiring 
every variation of energy, as to confine that tissue to one definite 
limit of extensibility ; for then, were that limit in the slightest de- 
gree exceeded, prejudicial consequences would ensue. 
May not the tonic power possessed by voluntary muscle — a 
power independent of that resulting from the immediate exercise 
of volition — be, like volitional power, to some extent capable of 
adjusting itself according to circumstances, in muscles for the time 
being not distinctly obeying the commands of the will] 
I have next a few remarks to make with reference to Mr. 
Mayhew’s observations on certain “ligamentous bands,” .connected 
with the flexor tendons of the fore leg. Although a description of 
these “ bands” is not to be found in our text books on veterinary 
anatomy, still they force themselves on the observation of every 
one who dissects the fore extremity of the horse with ordinary care. 
They are formed, as described by the author of the essay, one 
above the knee, proceeding from the posterior and inferior part of 
the radius ; the other below the knee, proceeding from the lower 
row of carpal bones and posterior surface at the superior extremity 
of the metacarpal bones, both of these bands pass inferiorly to be 
attached to the flexor tendons. Contained between them is a large 
synovial bursa, over which the flexors of the foot and pastern pass 
to their insertions. From the situation and connexions of the 
“ structures” alluded to, the idea could scarcely fail to follow, that 
they were placed here in order to protect the muscular fibre from 
shocks and injuries to which it would be liable, had we no such 
provision existing. Professor Dick, in his lectures, when speak- 
ing of the anatomy and uses of various parts of the fore leg, to- 
