A textbook of physiology / By M. Foster.

  • Michael Foster
Date:
1880
Catalogue details

Licence: Public Domain Mark

Credit: A textbook of physiology / By M. Foster. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    orally called excretions. The distinclioii between the two is an unimportant and fre(iuenlly accidental one. Tiie energy expended in the movements of the amceha is snpi)lied by the chemical chanucs goini; on in the proto- plasm, by the breaking np of bodies possi'ssing much latent energy into bodies possessing less. Thus the metabolic changes wiiich the food (as distinguished from the undi- gested stulf mechanically lodged for awiiile in the body) undergoes in passing through the protoplasm of the amceiia are of three classes: those prei)aratory to and culminating in the conveision of tiie food into protf)|)lasm, tlujse con- cerned in the discharge of energy, and those tending to economize the immediate products of the second class of changes by rendering them more or less useful in carrying out the first. 5. It is respiratory. Taken as a whole, the metabolic changes are pre-ennnently processes of oxidation. One article of food, i. e.,one substance taken into the body, viz., oxygen, stands apart from all the rest, and one product of metabolism peculiarly associated with oxidation, viz., car- bonic acid, stands also somewhat apart from all the rest. Hence the assumption of oxygen and the excretion of car- bonic acid, together with such of the metabolic processes as are more especially oxidative, are frequently spoken of to- gether as constituting the respirator}' j)rocesses. 6. It is reproductive. The ijidividual amo?ba represents a unit. This unit, after a longer or shorter life, having in- creased in size l»y the addition of new i)r()to})lasm in excess of that which it is continually using np, may, by fission (or by other means), resolve itself into two (or more) parts, each of which is ca])able of living as a fresh unit or indi- vidual. Such are the fundamental vital qualities of the protoplasm of an amoeba; all the facts of the life of an amneba are man- ifestations of these protoplasmic qualities in varied sequence and sul)ordination. The higher animals, we learn from morphological studies, may be regarded as groups of amoebaj i)eculiarly asso- ciated togetlier. All tlie physiological jjhenomena of the higher animals are similarly tlie results of these fundamental qualities of protoplasm peculiarly associated together. The dominant princii)le of this association is the physiological
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