The Cerebro-spinal Fluid in the Human Subject. 345 



amount of reduction with Fehling's solution, gave both these tests in a 

 typical way. 



The fluid was tested for creatinine with negative results. 



The same results relative to the reducing substance have been 

 obtained over and over again in various specimens of this fluid. They 

 agree with the observations of nearly all writers on the cerebro-spinal 

 fluid, but differ from those of Kawratski,* who in a recent paper has 

 affirmed, principally from observations on the cerebro-spinal fluid of the 

 calf, that the reducing substance present is dextrose. 



The principal points to be noticed in the properties of the fluid 

 which lead to the conclusion that it is cerebro-spinal fluid are the 

 following : 



(1) Its clear, watery character. 



(2) Its low specific gravity. 



(3) The small amount of proteid in it and the absence of albumin. 



(4) The presence in it of a substance which reduces Fehling's solu- 



tion, but is not dextrose. It is possibly a substance related to 

 pyrocatechin. 



In comparison with this fluid, we examined also the secretion in some 

 cases of true nasal hydrorrhcea. This fluid is opalescent, somewhat 

 viscid, and on microscopic examination shows amorphous matter with 

 mucous corpuscles. It gives with acetic acid a precipitate of mucinoid 

 nature. It sometimes does and sometimes does not contain a reducing 

 substance, and this substance when present is sugar. 



A quantitative analysis of one of these nasal fluids showed that the 

 percentage of solids, especially organic solids, is higher than in cerebro- 

 spinal fluid. The results of the analysis are as follows : 



Per cent. 



Water 98-792 



Total solids 1-208 



Pr oteids (including mucin) 0*260 



Other organic substances 0*163 



Inorganic substances 0*785 



Our observations on the characters of the cerebro-spinal fluid were 

 followed by others in which we sought to answer the following ques- 

 tions : 



The rate of flow. 



The difference of composition at different times of the day. 



The influence of straining, posture, and abdominal compression on 



the flow and composition of the fluid. 

 The effect on blood pressure of intra-venous injection of the fluid in 



animals. 



* < Zeifcs. f. Physiol. Chem.,' 1897, vol. 23, p. 532. 



