694 THE POPULAR SCIENCE MONTHLY. 



fully applied to resist poisoning by carbonic oxide. This gas, formed 

 by the combustion of charcoal and the oxygen of air, is a powerful 

 poison. Breathed in moderate quantity, it induces death by well-de- 

 fined action ; the carbonic oxide, acting on the blood-globules, dis- 

 places their oxygen, and forms a stable combination with them, which 

 is inert as regards vital properties. The constituent elements of the 

 organs soon cease to act, and they die as they do after arterial 

 haemorrhage. For some hours, immediately after the poisoning, the 

 blood-globules only are concerned, the other tissues remaining un- 

 touched ; it will be enough, then, to restore a healthy state, to empty the 

 vascular system, and replace the poisoned blood by new blood, and life 

 will revive. Thus the history of transfusion once more proves that 

 triumphs in the healing art may find their starting-point in the physi- 

 ologist's table, as advances in industrial art often originate in the 

 chemist's alembic. 



In the centuries regarded as a whole, the epoch oi*Harvey and our 

 own seem to belong to a similar period. The demonstration by physi- 

 ology of the individual life of the parts, and the practical applications 

 of transfusion, are wholly modern, as the circulation of the blood itself 

 is. In ancient days the general belief was, that the life dwells in the 

 blood, andyet some ancients seem to have had a suspicion that the ele- 

 ments of the organization live of themselves, and that, perhaps, the 

 blood has a movement of circulation. Yet the ancients observed the 

 life of the parts only in their outward forms. It is as a child studies 

 the works of a watch : give it to him, and he is satisfied to hear it tick ; 

 open it, and he follows with his eye the movement of the wheels, but 

 does not go further than to note appearances. Progress comes with 

 age, and the child, seeing the same watch when he is a grown man, 

 asks why and how it goes ; taught by experience, by dint of persever- 

 ance and labor, he takes off and replaces every wheel, gains a precise 

 idea of the mechanism of each part, and the arrangement of the whole 

 is then clearly understood. Men of science in our times have studied 

 the human machine so : the life of the parts has not only been observed, 

 but traced and detected in its most secret machinery. Transfusion of 

 blood, so useful in this respect, never acquired any true scientific im- 

 portance in the seventeenth century. At first it appears as a universal 

 panacea, aiming at the mastery of life, and triumph over disease itself. 

 We have seen how the mere imaginings of that idle dream passed away. 

 In our day the true method, the method of observation, is rightly hon- 

 ored, and scientific questions, no longer agitated with mere parade of 

 eloquence, are modestly studied by their facts in the seclusion of labo- 

 ratories. Transfusion again comes up, but not with its old extravagant 

 pretensions ; it no longer aspires to give universal, indefinite life. Re- 

 duced to the simple duty of a scientific process, it unveils the most 

 mysterious secrets of the organization ; it throws light upon the life 



