IN MEDICAL SCIENCE. 7 



portals of the hall of science. Look in with me, then, 

 while I attempt to throw some rays into its interior, 

 which shall illuminate a few of its pillars and cornices, 

 and show at the same time how many niches and al- 

 coves remain in darkness. 



Science is the topography of ignorance. From a few 

 elevated points we triangulate vast spaces, enclosing in- 

 finite unknown details. We cast the lead, and draw up 

 a little sand from abysses we shall never reach with 

 our dredges. 



The best part of our knowledge is that which teaches 

 us where knowledge leaves off and ignorance .begins. 

 Nothing more clearly separates a vulgar from a supe- 

 rior mind, than the confusion in the first between the 

 little that it truly knows, on the one hand, and what it 

 half knows and what it thinks it knows, on the other. 



That which is true of every subject is especially true 

 of the branch of knowledge which deals with Hving 

 beings. Their existence is a perpetual death and re- 

 animation. Their identity is only an idea, for we put 

 off our bodies many times during our lives, and dress 

 in new suits of bones and muscles.* 



" Thou art not thyself; 

 For thou exist' st on many a thousand grains 

 That issue out of dust." 



* " Occasio enim prseceps est propter artis materiam, dico autem cor- 

 pus, quod continue fluit et momento temporis transmutatur." — Galen. 

 Com. in Aphorism. Hippoc. I. 1. 



