48 FROM FISH TO PHILOSOPHER 



cemed with quantitative studies of the filtration rate and 

 the renal blood flow and the physiological regulation of 

 these functions, and of the detailed operations involved 

 in tubular reabsorption and excretion. Students who 

 have been away from their elementary textbooks scarcely 

 ten years deplore the fact that the subject matter cur- 

 rently appearing in the technical journals is decorated 

 with mathematical equations, intricately concerned with 

 enzyme systems and energy transformations, and casu- 

 ally displays utterly new concepts developed since 

 Cushny's time— all welded together by quantitative prin- 

 ciples. This current hterature is, of course, deeply con- 

 cerned with man, with his heart and circulation and 

 kidneys, and his misfortimes in disease, but human 

 physiology is only a part of the story: even as the foun- 

 dations of renal physiology were established through 

 studies on many diverse animals, so today's research 

 ranges profitably through the spectrum of sharks, rays, 

 skates, the fresh- and salt-water fishes, the frog and mud 

 puppy, the alligator and the snake, the chicken, and a 

 variety of mammals. The dog has contributed more to 

 our knowledge of renal function (as it has to many other 

 areas of medical science) than any other animal not ex- 

 cluding man himself; not only is it docile, intelligent, and 

 and easily trained to co-operate, but also, in respect to 

 renal function, it closely resembles man. A dog we called 

 Blitz, who came into the writers care in October of 

 1939 and had to be sacrificed in 1951 because of senility, 

 served for twelve years as the co-operative subject of 

 renal research for many yoimg investigators whose 

 names are now illustrious in the annals of American 

 medicine, as well as for students from Italy, France, Hol- 

 land, England, Denmark, Sweden, Argentina, Chile, and 

 Mexico. It was largely on Blitz that the writer and his 

 collaborators worked out the method for measuring the 

 renal blood flow that is now used to measure that func- 

 tion in man in every coimtry named. 



