( 103 ) 



and the transition-temperatures may lie at different distances from 

 each other. 



The method given enables us to deduct the phenomena in each 

 particular case and promises to be an important expedient in solving 

 the complicated phenomena that appear in the congealing and the 

 consequent changes in alloys. 



Physiology. — On the influence of salt-solutions on the volume 

 of animal cells, being at the same time a contribution to our 

 knowledge of their structure. By Dr. H. J. Hamburger. 



My investigations concerning the connection which exists between 

 the power of salts to attract water and their power to extract 

 colouring matter out of the red blood-corpuscles, led to the hypothesis 

 that for every salt a solution might be found in which the cor- 

 puscles would retain the same volume that they have in their own 

 serum. This supposition proved to be correct and it could moreover 

 be shown that those solutions which left the volume unchanged 

 represented a precisely equal hygroscopic power. 



The experiments referred to, made in 1884 and suggested by the 

 classic analysis of the phenomena of turgescence in plant-cells by 

 our countryman, Hugo de Vries, have been to me as well as to 

 others the point of departure for a series of researches which among 

 physiologists and pathologists have awaijened a constantly increasing 

 interest in the new doctrine of osmotic pressure. To this result the 

 theory of electrolytic dissociation of van 't Hoff and Arrhenids 

 has of late contributed. And in combination with each other these 

 two theories are on the way to clear up many a dark point in the 

 domain of physiology. One might have supposed that in the 

 course of 14 years other animal cells would have been inves- 

 tigated in the same way as have been the red blood-corpuscles. 

 This, however, has not been the case. For various purposes in- 

 deed the hygroscopic power of fluids, such as blood, lymph, serous 

 fluid, milk, has been studied; to the serous and mucous mem- 

 branes, indeed, fluids of different osmotic pressure have been offered 

 for absorption, in order to deduce from the change in this osmotic 

 pressure data for the knowledge of the resorption process; but 

 the influence of salt solutions on any other than the red blood-colls 

 has not yet been investigated. And yet for more than one reason 

 this is to be desired. In the first place in order to control the 

 inferences that have been drawn from the observations made with red 

 blood -corpuscles, and to decide many differences of opinion which 



8* 



