Aristotle : On the parts of animals / translated, with introduction and notes by W. Ogle.

  • Aristotle
Date:
1882
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Licence: Public Domain Mark

Credit: Aristotle : On the parts of animals / translated, with introduction and notes by W. Ogle. Source: Wellcome Collection.

    153/316 page 105
    themselves and can seize hold of their food, and that they are sensible of objects which come in contact with them, they must be considered to have an animal nature. The like conclusion follows from their using the roughness of their bodies as a protection against their enemies. But on the other hand they are closely allied to plants, firstly by the i'mperfection of their structure, secondly by their being able to attacli*themselves to the rocks with great rapidity, and lastly by their having no visible residuum, notwithstanding that they possess a mouth. Very similar again to the Acalephse, are the Starfishes. For these also seize hold of their prey, and suck out its juices, and thus destroy a vast number of oysters.®® ’ At the same time they present a certain resemblance to such animals as the Cephalopods and Crustacea, inasmuch as they are free and un- attached. The same may also be said of the Testacea. Such then is the structure of the parts that minister to nutrition, and which every animal must necessarily possess. But besides these organs it is quite plain that in every animal there must be some part or other which shall be analogous to what in sanguineous animals is the presiding seat of sensation. Whether an animal has or has not blood, it cannot possibly be without this. In the Cephalopods this part consists of a membrane, containing fluid, through which runs the gullet on its way to the stomach. It lies rather towards the dorsal surface of the animal, and is by some called the fnytis.^ Just such another organ is found in the Crustacea, and is known in them also by the same name. This part is formed by a ’ combination of fluid and solid, and is, as before said, traversed by the gullet. For had the gullet been placed farther back, between the mytis and the dorsal surface of the animal, the hardness of the back would have interfered with its due dilatation in the act of deglutition. On the outer surface of the mytis runs the intestine; and in contact with this latter is the ink-bag, which is thus removed as far as possible from the mouth, while a considerable interval divides its irritating fluid fropi the nobler and sovereign parts.®® The position of the 7nytis shows that it corresponds to the heart of sanguineous animals ; for it occupies the self-same place. The same is proved by the sweetness of its fluid, which has the character of concocted matter and resembles blood.®® In the Testacea the presiding seat of sensation is in a cor-
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