94 ANIMAL EXPERIMENTATION 



legislature the counsel for the petitioners sought to prove 

 that in teaching a natural science, such as physiology, 

 demonstrations are no better than books. Most of the 

 persons whom he brought forward to support this medie- 

 val notion had never seen any physiological experiments. 

 One witness, who was once a teacher of anatomy, believed 

 that the structure of a dead organ could not be learned 

 without studying the organ itself; but she was sure that 

 the action of that organ in life could be learned from a 

 book. It is perhaps natural that those who confess that 

 they have not seen Nature, but have only heard about her, 

 should try to comfort themselves with the idea that hear- 

 say is like personal acquaintance. This is a delusion 

 which is increased by their incapacity to appreciate the 

 fundamental difference between the natural sciences and 

 other disciplines, for example, mathematics and the law. 

 It is true that in both the natural sciences and the law the 

 student is now directed to the original source in science 

 to the natural object or process, in law to the cases and 

 decisions, which are in fact the law. But there is this 

 important difference. The material of the law is in books. 

 Words give with accuracy the principles and rulings which 

 constitute the law. It is not so in natural phenomena. 

 These cannot be well described. If words could serve, 

 the blind would see. You cannot know a man's voice 

 until you have heard it. In the Harvard laboratory for 

 physiological research the Committee on Probate and 

 Chancery of the last legislature were shown the heart 

 of a tortoise which had been taken from the body after 

 the head of the animal had been cut off. A glass tube 

 had been fastened in an artery leading from the heart and 

 a second glass tube in a vein leading to the heart. The 

 extirpated heart was pumping steadily. The blood which 

 was allowed to flow from a reservoir into the organ 

 through the venous tube was pumped up through the 



