Preface to the Third Edition. 



IT took less than three months for the Second 

 Edition to be exhausted, a pleasing sign that this new 

 field of research has excited much interest. The 

 number of works which have been completed on the 

 basis of the principles there laid down, and of the 

 methods there disclosed, exceeds one hundred and 

 twenty ! Every week brings forth new works. I am 

 not sure whether that ought to give me entirely un- 

 broken satisfaction. The fundamental works, which 

 have arrived at a definite conclusion in regard to the 

 elaboration of the dialysation process and of the 

 optical method, have been produced during the last 

 twelve years or so. The " theoretical : part, which 

 pointed to the possibility of a sero-diagnosis of the 

 functions of organs, was practically established six 

 years ago. Experiments on animals were started 

 on a large scale, so as to allow for all possibilities. 

 Over and over again doubts cropped up which had 

 to be settled. The astonishing result was found that, 

 in disturbances of certain organs, only their albu- 

 minous constituents suffer decomposition. These 

 discoveries were not made public, and only those 

 results, which were established in investigations on 



