The Cerebro-spmcd Fluid in the Human Subject. 



349 



B. Fluid collected while she was lying down. The percentage of 

 solids was 1'03. 



The effect of the horizontal posture is in the same direction, though 

 not so marked as the effect of straining. This is what was to be 

 expected, for the horizontal posture would not raise the venous, and 

 thus the cerebral, capillary pressure so much as powerful expiratory 

 efforts would. Moreover, the arterial pressure falls during quiet rest 

 in the recumbent posture, as one of us has determined (L. H.).* 



In order to note the effects of straining on the retinal circulation, Mr. Vernon 

 Cargill was asked to examine the patient, and he kindly reported as follows : 

 " I noticed that when a straining effort was mads, a decided but transitory narrow- 

 ing of the retinal arteries on and adjacent to the disc, and also a marked pulsation 

 in the trunks of the retinal veins occurred." 



The transitory narrowing of the arteries points to the temporary lowering of the 

 aortic pressure, while the pulsation of the veins is a sign of the capillary engorge- 

 ment due to venous congestion. 



Experiments made with Abdominal Compression. 



These experiments were made in order to complete and confirm 

 those just recorded. The patient was seated, and the abdomen was 

 compressed as firmly and evenly as possible by one of us (StC. T.), 

 spreading both hands over the front of the abdomen. The number of 

 drops per minute were counted as before, and periods of compression 

 lasting five minutes were alternated with periods of the same duration, 

 during which the patient was sitting quietly. 



The following table gives the results succinctly : 



The fluids from experiments " A " and " C " were mixed together ; 

 also those from experiments " B " and " D." Determination of the 

 total solids gave the following results : 



" A " and " C." Fluid collected during abdominal compression. 

 Percentage of solids, 0'68. 



" B " and " D." Fluid collected while the patient was sitting up- 

 right quietly. Percentage of solids, 1*14. 



* ' Phys. Soc. Proc.,' January 15, 1898. 



