52 Dr.. G. Oliver. [May 18, 



s'expliquer par les theories actuelles, et sent dus simplement a I'exquise 

 sensibilit^ du cohereur, W s'ils ne prouvent pas que les ondes se 

 reflechissent sur les couches superieures de 1'utmosphere rendues con* 

 ductrices par leur extreme rarefaction. 



* The Measurement of Tissue FluidUn Man. Preliminary Note." 

 By GEORGE OLIVER, M.D., F.R.C.P. Communicated by Sir 

 LAUDER BRUNTON, F.K.S. Beceived in revised fonn May 18, 

 -Bead June 11, 190:'.. 



The object of this preliminary note is to indicate a method by which 

 the tissue fluid in man may be measured, thus enabling the observer 

 to ascertain the conditions under which it is effused and disposed of. 



In the course of some observations made with the view of eliminating 

 tissue fluid as a cause of variability in the samples of blood obtained 

 for examination, I found that the rolling of a tight rubber ring over 

 the finger from the tip to beyond the interphalangeal joints will, as a 

 rule, considerably raise the percentages of the blood corpuscles, and of 

 the haemoglobin. I could not arrive at any other conclusion, than that 

 the ring not merely empties the vessels, but likewise clears away any 

 tissue fluid present in the skin and subcutaneous tissues. The needle, 

 in puncturing the capillaries, liberates a certain portion of lymph from 

 the areolar tissue which surrounds them, and this dilutes the blood. 

 When, however, both fluids, have been dispersed as much as possible 

 by the compression of the firm rubber ring, a puncture made just before 

 removing the ring yields blood per se ; for the blood instantly returns 

 to the vessels, whereas an appreciable interval must elapse before the 

 lymph reappears, or is exuded afresh. I, therefore, inferred that the 

 reading of the difference in the percentage of the corpuscles, or of the 

 hsemoglobin, before and after the use of the ring, provides a measure 

 of the tissue-lymph, and makes the study of the circulation of it i 

 man possible. 



This simple method having furnished somewhat unexpected results, 

 I naturally accepted them at first with reserve ; and, for some time, 

 the data were allowed to accumulate, until at last it was quite apparent 

 that they invariably fell into the same order. Inasmuch as the method 

 did not provide results which were exceptional or erratic, or contra- 

 dictory and unaccountable, reliability on it became gradually established 

 by the mere repetition of the observations. 



,A number of observations have been made on normal subjects 



leading a quiescent life, with comparative rest of the muscles ; and on 



/ns subjected to varying degrees of exercise, and to different 



