436 Canadian Record of Science 



countries and into the various reasons assigned for the 

 predominant condition of right-handedness, by physi- 

 cians, anatomists and physiologists, some giving an 

 opinion as Sir C. Bell, that not only is man right- 

 handed, but also right-footed, and that the right side 

 is stronger than the left physically, others stating that 

 the blood supply is better to the right side than the left, 

 again that it is due to the difference in the blood supply 

 to the brain, and even to the difference in size of the 

 two sides of the brain. 



If the course of the blood be, starting from the apex 

 of the left ventricle through the ventricle into the aorta, 

 and then a line be drawn as it were through the left 

 ventricle and the course of the ascending aorta, through 

 the arch of the aorta, and down to the promentary of 

 the sacrum, it will be found to be represented thus, and 

 if a plan were made looking down from above, it would 

 be represented as a circle drawn from left to right, 

 passing upwards and to the right in a curved manner, 

 then still upwards and back at the same time passing 

 gradually to the left side of the vertebral column, then 

 down the left side of vertebral column, gradually passing 

 to the centre thereof opposite the promontory of the 

 sacrum, where it divides into two common iliac arteries. 



In this course the aorta gives off the two small 

 branches to supply the heart, the coronaries, then it 

 passes on and where it begins to turn back and to the 

 right side it gives off the large arteria innominata which 

 divides into the right common carotid and subclavian, 

 the carotid supplying the right side of the head and 

 brain and the subclavian the right upper extremity. 

 Passing on the arch of the aorta gives off from the upper 

 side of the arch the left common carotid and the sub- 

 clavian, the carotid supplying the right side of the head 

 and brain and the subclavian the right upper extremity. 

 Passing on the arch of the aorta gives off from the upper 

 side of the arch the left common carotid and a little 

 further on the left subclavian, and then passing down 



