1884.] The Upright Attitude of Mankind. 135 
Dr. Clevenger first discusses the position of the valves in 
the veins. The teleologists have long told us that the valves 
in the veins of the arms and legs assist in the return of 
blood to the heart against gravitation. But what earthly 
use has a man for valves in the intercostal veins which carry 
blood almost horizontally backwards to the azygos veins ? 
When recumbent these valves are an adtual obstacle to the 
free flow of the blood. The inferior thyroid veins which 
drop their blood into the innominate are obstructed by valves 
at their junction. Two pairs of valves are situate in the 
external jugular, and another pair in the internal jugular, 
but they do not prevent regurgitation of blood upwards. 
An anomaly exists in the absence of valves from parts 
where they are most needed, such as the venae cavae, the 
spinal, iliac, haemorrhoidal, and portal veins. 
But if we place man upon all-fours these anomalies dis- 
appear, and a law is found regulating the presence or absence 
of valves, and, according to Dr. Clevenger, it is applicable 
to all quadrupeds and to the so-called Quadrumana. Veins 
flowing towards the back — i.e., against gravitation in the 
all-fours posture— are fitted with valves ; those flowing in 
other directions are without. For the few exceptions a very 
feasible explanation is given. 
Valves in the haemorrhoidal veins would be useless to 
quadiupeds ; but to man, in his upright position, they would 
be very valuable. “ To their absence in man many a life 
has been and will be sacrificed, to say nothing of the dis- 
comfoit and distress occasioned by the engorgement known 
as piles, which the presence of valves in their veins would 
obviate.” 
A noticeable departure from the rule obtaining in the vas- 
cular system of Mammalia also occurs to the exposed 
situation of the femoral artery in man. The arteries lie 
deeper than the veins, . or are otherwise protected, for the 
purpose as a teleologist would say — of preventing serious 
loss of blood from superficial cuts. Translating this view 
into evolutionary language, it appears that only animals 
with deeply-placed arteries can survive and transmit their 
structural peculiarities to their offspring. The ordinary 
abrasions to which all animals are exposed, not to mention 
their onslaughts upon each other, would quickly kill off 
species with superficially-placed arteries. But when man 
assumed the upright posture the femoral artery, which in 
the quadrupedal position is placed out of reach on the inner 
part of the thigh, became exposed. Were not this defect 
greatly compensated by man’s ability to protect this part in 
