File:American journal of physiology (1898) (14781974132).jpg

Identifier: americanjourn01ameruoft (find matches)
Title: American journal of physiology
Year: 1898 (1890s)
Authors: American Physiological Society (1887- ) American Physiological Society (1887- ). Abstracts of papers presented at the fall meeting American Physiological Society (1887- ). Proceedings
Subjects: Physiology Physiology
Publisher: (Bethesda, Md., etc.) American Physiological Society (etc.)
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
ane manometer. The secondcurve was written by the armature of an electro-magnet placed in theprimary circuit of a du Bois-Reymond inductorium. The heavywhite line records the stimulation of the peripheral end of the vagusnerve with a weak induced current; the individual strokes of thearmature are blended, owing to the slow speed of the smoked paper.The third curve marks the number of drops of blood flowing throughthe coronary vessels, the recording apparatus being that used forthe experiment illustrated by Fig. 4. The fourth curve marks thetime in seconds. The weak excitation of the vagus diminished the ^ For the details of this method and a discussion of its sources of error, seeMagrath and Kennedy : Journal of experimental medicine, 1897, ii, p. 13. i6o W. T. Porter. frequency of ventricular contraction, but left the force unchanged.The volume of the coronary circulation lessened when the frequencyof contraction lessened, and was restored with the restoration of theformer frequency.
Text Appearing After Image:
Fig. 5. March 26, 1S96. Showing the lessening in the volume of the coronary circula-tion consequent on a lessening of the frequency of the heart-beat. The uppermosttracing is the pressure in the left ventricle of the isolated heart of the cat; the line be-low was drawn by the writing point of an electro-magnet placed in the primary cir-cuit of the inductorium, the broad, white band indicating the duration of vagusstimulation ; the next curve records the number of drops of blood passing throughthe coronary vessels ; and the lowermost tracing is the time, in seconds. The weakexcitation of the vagus finally lessens the frequency of contraction, — at once thevolume of the coronary circulation is also lessened. It would seem, then, that an increase in either the force or thefrequency of the contractions of the heart increases the volume ofblood passing through the coronary circulation by means of theperiodical emptying of the intramural vessels, — yet it would not beprudent to accept t

Note About Images