( 392 ) 



liquid curve at first and then appears outside, either on the tempe- 

 rature being raised, as is the ease with mixtures of triethjlamine 

 and water ^), or on lowering the temperature, as with propane and 

 methylalcohol ^) ; if in those eases a maximum vapour pressure exists, 

 this maximum may disappear in a manner similar to the one 

 sketched above. 



The above conclusions may be summarised as follows: 

 The critical mixing-point of two liquids does not coincide with a 

 point of maximum vapour pressure, if such a point exists; but the 

 latter point may sooner or later at some distance from the critical 

 point be enclosed inside the three-phase equilibrium; in the critical 

 point the liquid branch of the saturation curA-e in the ji — x diagram 

 has a point of inflexion with a tangent parallel to the .r-axis. 



university College, Dundee. 



Physiology. — "Sontethhu/ concernlmi the growth of the lateral 

 areas of the trunkdermatomata on the caudal portion of the 

 upper extremity" By Prof. C. Wjnkler from researches made 

 in connection with Di-. G. van Rijnberk. 



(Gomraunicated in the meeting of November 28, 1903). 



A methodical treatment of the dermatomata of the upper extremity 

 offers very considerable difficulties, which have been confronted for 

 the first time by the eminent labour of Sherrington, though to our 

 belief he has not wholly succeeded in conquering them. 



The first difficulty we encounter, wdien essaying their physiological 

 elaboration, is a technical one. The upper extremity transforms by 

 its growth the dermatomata (of neck and trunk) situated above 

 and beneath it. Owing to this transformation their extension-areas 

 overlap one another mutually in a very peculiar manner, and only 

 by means of cutting through numerous — sometimes from 7 to 9 — 

 adjacent posterior roots, it becomes possible to isolate them completely. 

 The operation therefore presents greater difficulties, its duration is 

 prolonged, its dangers are increased, partly because of the near 

 vicinity of the medulla oblongata, partly because of the presence of the 

 large perimedullar venous blood-reservoirs (air-embolus, hemorrhage). 



The experimental definition of the extension of a root-area on the 

 extremity, already more complicated than it is on the trunk, because 



1) KuENEN, Phil. Mag. (G) G, p. 637-G53, 



