50 PROF. GARROD ON THE INTERVERTEBRAL SUBSTANCE. | Feb. 6, 
It may not be out of place for me here to draw attention to one 
or two points which are associated with the erectness of the carriage 
of man, in contradistinction to the horizontal and oblique attitudes 
assumed by lower animals. 
The simple curve, concave ventrally, of the vertebral column of 
the higher Apes was most certainly shared by the human progenitor. 
In the young child it is found to exist. In its attempts to assume 
the upright carriage this progenitor must, equally certainly, have 
thrown the centre of gravity of its body directly above the hips, 
to do which it was necessary to bend the spine backwards. On 
account, however, of the thoracic region being rendered rigid by the 
attachment of its cage of ribs, and the sacrum being unmodifiable 
from its ankylosis, this flexion of the spine could only occur in the 
neck and loins ; consequently the spinal flexures in man may be ex- 
plained upon the assumption that the dorsal and sacral ventral con- 
cavities are the similar curves of the ancestral type, retained on 
account of the mechanical obstructions to their removal, whilst the 
ventral convexities of the yielding cervical and lumbar regions are 
the means by which the centre of gravity in the erect position is 
carried to a point directly above the hip-joints. 
This assumption of a vertical attitude by a creature originally 
differentiated for a horizontal position of its body, has produced but 
marvellously slight inconvenience. If it had resulted in many, man 
could scarcely have survived. There are one or two, however, which 
are most clearly traceable to this cause, including the painful tendency 
to prolapse, antiflexion, and retroflexion of the uterus in women, as 
well as crural hernia in both sexes, and inguinal hernia in the male. 
In mammalian animals with the body horizontal the weight of the 
uterus is transmitted to the abdominal walls, at the same time that 
the round and broad ligaments prevent it from leaving the pelvic 
region. In the Sloths and Bats these ligaments are still more called 
into play, on account of the peculiar attitudes assumed by them. No 
more satisfactory mechanism could be desired. But in the human 
species the condition is very different. The uterus is situated almost 
directly above the vagina; and the entire absence of any ligaments 
to suspend it, place it in a position of the greatest mechanical disad- 
vantage, especially when congested and depressed by stays. Unsup- 
ported, it a priagd bends forward or backwards, or even drops into 
the cavity of the vagina, and there finding nothing to obstruct it, 
becomes completely prolapsed. Similarly in inguinal hernia, the 
abdominal walls being abnormally extended in connexion with the 
lumbar curye, the tendency to rupture in the region of the inguinal 
canal must be greatly increased, as it must likewise be by the down- 
ward tendency of the yiscera. 
