Again, as already
said, the vessels continue their course through the other viscera, but
no vessel spreads through the heart. From this it is quite evident
that the heart is a part of the vessels and their origin; and for this
it is well suited by its structure. For its central part consists of a
dense and hollow substance, and is moreover full of blood, as though
the vessels took thence their origin. It is hollow to serve for the
reception of the blood, while its wall is dense, that it may serve
to protect the source of heat. For here, and here alone in all the
viscera and indeed in all the body, there is blood without
blood-vessels, the blood elsewhere being always contained within
vessels. Nor is this but consistent with reason. For the blood is
conveyed into the vessels from the heart, but none passes into the
heart from without. For in itself it constitutes the origin and
fountain, or primary receptacle, of the blood. It is however, from
dissections and from observations on the process of development that
the truth of these statements receives its clearest demonstration. For
the heart is the first of all the parts to be formed; and no sooner is
it formed than it contains blood. Moreover, the motions of pain and
pleasure, and generally of all sensation, plainly have their source in
the heart, and find in it their ultimate termination.
Pages:
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128