86 THE LAND-MARKS OF 



Mr Boag'3 ]\fj. Boag's theorvwas that the venom siib- 



tracted the oxygen of the blood, so leading to 

 death, and he founds this theory on four argu- 

 ments as he terms them ; with some of which, 

 however, it is difficult to concur. These four 

 arguments are : — 



1st. — " Man, and other warm-blooded animals, 

 exposed to an atmosphere deprived of oxy- 

 gen, quickly expire. The poison of a serpent, 

 when introduced into the blood, also causes 

 death, but carried into circulation by a wound, 

 and in very small quantity, its operation is com- 

 paratively slow and gradual." 



2^(1. — " The appearances on dissection in both 

 cases are very similar, the blood becomes of a 

 darker colour, and coagulates about the heart and 

 large vessels, the irritability of the fibres is 

 nearly in the same degree destroyed, and the 

 body has a strong tendency, in both instances, 

 to putrescency." 



3rd. — "Dr. Mead mixed the venom of the viper, 

 and healthy blood together out of the body, and 

 he did not perceive that it produced any change 

 in its appearance ; this arose from his mixing 

 a small quantity of the venom with a large 



