A text-book of human physiology (1906) (14767974904)

Identifier: textbookofhumanp00tige (find matches)

Title: A text-book of human physiology

Year: 1906 (1900s)

Authors: Tigerstedt, Robert, 1853-1923 Murlin, John R. (John Raymond), b. 1874, tr

Subjects: Physiology

Publisher: New York and London, D. Appleton and Co.

Contributing Library: Columbia University Libraries

Digitizing Sponsor: Open Knowledge Commons

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uently permits of very valuable conclusions.Especially is this true in the case of organs like the thyroid gland and theadrenal bodies, which to direct observation disclose no sign of their func- 6 GENERAL PHYSIOLOGICAL METHOD tious. Extirpation and transscction represent important methods of researchin studying the functions of the central nervous system. It cannot be deniedhowever that the resuUs of excision methods are unfortunately too oftenvery ditlicult of exjilanation. and that their interpretation is not infrequentlymade still more ditlicult by unintentional lesions. §3. EXPERIMENTS ON SURVIVING ORGANS In the cold-blooihd aiiinidls niani/ onjans remain alire for a long timeafter the death of ^he organism, even when they have been cut out of the body.By virtue of this property it has been possible to collect a great mass of mostimportant facts. Our knowledge of the general properties of nerve and musclerests for the most part on experiments with exsected organs. Organs removed

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Fig. 1.—Illustrating ttie u.se of the graphic method in recording the simple contraction of afrogs muscle. For description, .see text. from the Ijody remain still longer alive if, as was first done by Ludwig and hisschool, they be artificially nourished with blood. Under such conditions it is))Ossible also to maintain organs of warm-blooded animals alive for a consid-(•ral)le time after death of the body as a whole. Organs removed from theIjody which remain capable of activity are called surviving organs. § 4. THE GRAPHIC METHOD Functions of organs are not infrequently expiessed by outward move-ments of some kind, which as a rule are so rapid that their details cannot befollowed by the naked eye. They can be studied very exactly, however, ifone can hit upon a method by which the movements record themselves upon amoving surface (graphic method, Ludwig, 1847). Since this method finds very wide application in most branches of physiol- THE GRAPHIC METHOD ogy, it is necessary to descrtextbookofhumanp00tige

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1906

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