68o THE POPULAR SCIENCE MONTHLY. 



fun, and will give rise to about as much pain as a not too enthusiastic 

 sportsman in a short sporting-season. 



We have now to ask : What justification does he plead for this death 

 and this pain? What good to mankind is thereby wrought which 

 could not otherwise be gained ? 



His answer is, that the science of physiology is thereby advanced ; 

 that our knowledge of the laws of life has, in the main, been won by 

 experiments on living animals. He, of course, cannot, and no one can, 

 tell the " might have been." Without any such experiments, physics 

 and chemistry, aided by mathematics, might have synthetically re- 

 solved the problems of life (though even then it might be said that 

 both physics and chemistry sprang from the older biologic lore, and 

 not so long ago a common physiological preparation, the muscle and 

 nerve of a frog, started a new epoch in physics) ; but, as a matter of 

 history, experiments on living animals have been the stepping-stones 

 of phyiological progress. 



The great Vesalius, the founder of modern anatomy, turning his 

 thoughts to the uses of the structures he had so well described, saw 

 clearly that the problems opening up before him could be settled only 

 by vivisection. In his great work, " De Corporis Humani Fabrica," 

 may be read the evidence, not only that he performed experiments on 

 living animals, but that, had he not in so inscrutable a way forsaken 

 the arduous pleasures of learning for the gossip of a court, those ex- 

 periments would have led him up to and probably beyond the dis- 

 covery which years afterward marked an epoch in physiology, and 

 made the name of Harvey immortal. He, indeed, sowed the seed 

 whose fruit Harvey reaped. The corner-stone of physiology, the doc- 

 trine of the circulation of the blood, was not built up without death 

 and pain to animals. To-day, it is true, much of the evidence touch- 

 ing the flow of blood may be shown on a dead body, yet the full proof 

 cannot be given even now without an experiment on a living creat- 

 ure ; and certainly Harvey's thoughts were guided by his study of the 

 living, palpitating heart, and the motions of the living arteries, quite 

 as much as by the suggestions coming from dead valves and veins. 



After Harvey came Haller, whose keen intellect dispersed the misty 

 notions of the spiritualists, and by the establishment of the doctrine of 

 "irritability" laid the foundations of the true physiology of the nervous 

 system : he too, in his work, wrought death and suffering on animals. 



Another great step onward was made when Charles Bell and Ma- 

 gendie, by experiments on animals more painful than any of the pres- 

 ent day, traced out the distinction between motor and sensory nerves; 

 and yet another, when Marshall Hall and others demonstrated by 

 vivisections the wide-spread occurrence and vast importance of reflex 

 actions. 



What was begun with death and pain has been carried forward by 

 the same means. I assert deliberately that all our real knowledge of 



