3O0 Fische/s Theory of Edema [Dec. 



or Peritoneum. Let Frey's finding be noted that these anesthetics do 

 not interfere with the absorption of water from the gastro-intestinal 

 tract. We are not surprised in the face of our explanation to note that 

 Frey found this retention of water to occur just the same whether he 

 had previously bled the animal or had cut the nerves to the kidneys, or 

 changed the posture of the animal. Not even when he gave phloridzin 

 or salicylic acid in an attempt to " stimulate " the kidneys did he get a 

 urinary flow. According to our ideas of urinary secretion such a result 

 is entirely to be expected. None of these procedures affect the affinity 

 of the colloids of the tissues for water except as some increase it. 

 (Page 198.) 



The continuance of an absorption of water from the gastro-intestinal 

 tract while none was being secreted through the kidneys is easily ex- 

 plained by the increased affinity of the colloids of the tissues generally 

 for water. On this basis it is also an easy matter to explain the in- 

 creased absorption of salt Solution from the peritoneal cavity in 

 nephrectomized animals, as observed by S. J. Meltzer and Salant." 

 The retention of substances that should be secreted through the kidneys 

 poisons the tissues and increases the affinity of their colloids for water. 

 (Page 198.) 



Let US recall here our division of the urinary secretory system into 

 its three parts : the blood, the secreting membrane, and the urine, and 

 our brief characterization of the first as a liquid colloid in which 

 various crystalloids are dissolved, the second as a solid colloid also con- 

 taining various crystalloids, and the third as a watery Solution of various 

 crystalloids (practically) free from colloids. Thus far our discussion 

 has shown that under the conditions normally existing in the body no 

 water can be introduced into the blood without getting the secretion of 

 an equal amount as urine. And what is secreted as urine is water and 

 only secondarily do substances come to be dissolved in it, so that it 

 assumes a chemical composition which permits it to be characterized as 

 urine. Let us see now what must happen if some soluble^^ (or pseudo- 

 soluble) substance is introduced into the blood. To simplify the prob- 

 lem and not make our discussion unnecessarily long, let us think of the 

 blood as one homogeneous system, and the urinary membrane as 

 another. Under such circumstances one of three possibilities presents 

 itself from a physico-chemical Standpoint. The dissolved substance 



"Meltzer and Salant: American Medicine, 1904, viii, p. 194- 

 "The word soluble is used in these paragraphs in its broadest sense, so as to 

 include even the pseudo-soluble (colloidal) substances. 



