404 



THE CIRCULATION. 



to three minutes. This has been prbvect by the following experi. 

 ment, which has been made and repeated many times at the 

 Columbia Veterinary College, New York : The jugular vein was 

 opened on one side of the neck, into which saline matter or poison was 

 injected ; on the opposite side the carotid artery was tapped. In fif- 

 teen seconds the first traces of the substance injected could be detect- 



Fig. 694. — Ths Heart and Principal Vessels ; Left Face. 



a, Bight ventricle; ft, Left ventricle; c, Right auricle; d, Left auricle; e, Pulmonary 

 artery; f, Pulmonary veins; g, Anterior aorta; h, Left axillary artery; i, Right axillary 

 artery, or brachiocephalic trunk; p, Carotid arteries; q, Posterior aorta; x, Vena azygos; 

 y, Thoracic ducts; z, Embouchure of that vessel, placed near the origin of the anterior vena 

 cava. 



ed in the blood ; in twenty seconds it was found very plainly. But 

 while it is known that the main body of blood makes the shorter 

 pulmonary circuit, that part going to the extremities most distant 

 from the heart requires much longer time ; but it is assumed that all 

 the blood in the body makes its entire circuit in the short period of 

 from two to three, minutes. 



I refer to this fact, which is not familiar to the average reader, 

 to show the great importance of not subjecting the horse.to such in- 



