256 
BARLOW ON TENDINOUS STRUCTURES. 
the diseases to which he has “ hazarded” to consider them liable, 
should be considered as having “ been hitherto unobserved.” 
With reference to the first of these heads, regarding the inade- 
quacy of muscular and the power of tendinous structure in sus- 
taining weight and the integrity of articulations, either in a state of 
activity or otherwise, I have little to say additional to what is ex- 
pressed by Mr. Mayhew; for his statements, although conveying 
a summary of what is well known to be the case, do not apparently 
contain any thing regarding the properties of these tissues which 
has “been hitherto unobserved.” Numerous evident illustrations 
of the uses which white and yellow fibrous tissues serve in 
exempting muscular substance from fatigue and stress are seen in 
the body of the horse. The fore and hind extremities afford many 
instances of this, in the connexions which some of their muscles 
and bones possess with special arrangements of tendinous and 
ligamentous structures. The way in which the head is sustained 
is a case shewing, as is well known, the admirable adaptation of 
the almost insensible yellow elastic tissue in passively maintain- 
ing a condition which it would require considerable expenditure 
of muscular power to execute. The arrangement of tendinous 
structure, forming the inferior boundaries of the abdominal cavity, 
exemplifies a fulfilment of a corresponding end by corresponding 
means. It may be objected to the latter example, that the weight 
of the abdominal viscera, though falling immediately upon the in- 
sensible aponeurotic structure, must of necessity be determined 
ultimately to the muscles of which the aponeuroses are but conti- 
nuations. But to obviate, under all reasonable conditions, the 
fatigue or injury likely thereby to be induced, there is, enveloping 
both tendinous and muscular structure, a dense expansion of yellow 
elastic fibrous tissue, possessing attachments bony or otherwise, 
corresponding with those of the external oblique muscle of the 
abdomen, and which of course affords, as in the horse and ox, a 
powerful yet untiring support to parts which might probably be 
inconvenienced by fatigue and structural injury also. This is a 
structure not noticed by many veterinary anatomists*, yet so obvious 
is it, both as to situation and use , that I could scarcely suppose it 
had “ been hitherto unobserved.” In every muscle of the body 
destined for the performance of actions energetic in their nature, 
we find, as is well known, a large proportion of tendinous fibre ; 
for instance, the masseter and pterygoid muscles in the head, the 
serratus magnus, longissimus dorsi, and others on the trunk, are 
familiar examples. And in animals like the horse, whose structural 
conformation so beautifully adapts them for peculiar purposes, we 
* Mr. Percivall has described it under the name of Faschin Transversalis ; 
and has represented it to be “ of essential service in sustaining the burden of 
the dependent viscera .” — Anatomy of the llorse, pp. 127-8. 
