548 STUDIES IN GENERAL PHYSIOLOGY 



point, they gain in significance. They teach us that we can 

 impart to a tissue new properties by changing the quality 

 and the relative proportions of the ions in combination with 

 the proteids. The characteristic qualities of every tissue 

 are partly due to the fact that its ion proteids contain certain 

 ions in definite proportions. Any change in this proportion 

 is accompanied by a change in the properties of the tissue. 



Ten years ago I started upon experiments in which I 

 substituted at desire one organ for another or transformed 

 one organ into another (heteromorphosis). The agents I 

 used for this purpose were various forms of contact, gravita- 

 tion, and light. But the number of animals in which the 

 phenomena of heteromorphosis could be controlled was 

 rather limited. I concluded at that time that it would be 

 necessary for the development of this technical or con- 

 structive side of biology to fiiia a more elementary point of 

 attack. The ion proteids, on account of the ease with which 

 their properties can be changed by a change of their ions, 

 seemed to offer the desired opportunity. I therefore decided 

 to devote last summer at Woods Hole entirely to experiments 

 in this direction. Marine animals which live in a medium 

 having a high concentration of ions seemed to offer better 

 opportunities than fresh-water or land animals. 



A brief report of one part of the summer's work was 

 published in this periodical. 1 Since then Dr. W. Pauli, of 

 Vienna, has published an address in which he reaches similar 

 conclusions on ion proteids independently. 2 His conceptions 

 are based on experiments upon the physical qualities of 

 proteids. His address appeared too late to influence me in 

 my work or my ideas, but the clearness of his results and 

 statements was a very welcome support. He speaks in his 



1 American Journal of Physiology, Vol. Ill, p. 135. 



2 W. PAULI, Ueber physikalixch-chemische Methoden und Probleme in der 

 Miitizin (Wien, 1900); and "Ueber die physikalischen Zustandanderuiigen der 

 EiweisskOrper," Wiener akademischer Anzeiger, October 12, 1899. 



