ß2 "^ Lindhard. 



children and nervous persons — contains more leucocytes per unit 

 than the succeeding drops. They also believe that this is due to 

 the fear of the person experimented on for the prick of the needle. 



I have several times observed this condition in myself, though 

 I had no feeling of anxiety; I am therefore inclined to think that 

 the true cause lies in vasomotor changes. After incision with the "Snep- 

 pert" (hidden needle) we may often notice a distinctly local ischæmia, 

 frequently lasting some time, which is followed by a very copious 

 flow of blood, and it seems to me, therefore, that a sudden vaso- 

 motor change might well have some effect on the number of the 

 leucocytes, even if distinct paresis of the capillaries is of no impor- 

 tance in this regard. 



I have also observed, however, suddenly occurring but very 

 quickly disappearing changes in the blood-pressure (and pulse) owing 

 to mental impressions and have been able to follow in part the 

 corresponding changes in the number of leucocytes. 



Diast. blood-pressure Number of leucocytes 



145 



175 



7067 



5578 



The first sample of blood was taken two minutes after the 

 measurement of the blood-pressure, the second about 5 minutes 

 later. I noticed suddenly during the investigation that the pulse of 

 the medium had become hard and tense (on hearing conversation 

 outside the room) and measured the blood-pressure over again in 

 order to determine the increase; during the taking of the last sample 

 the pulse was again as at the beginning. As will be seen from 

 Fig. 3 (L. ^^/2 07, p. 71) the two low^est values are the "normal" for 

 the date mentioned. 



It is undoubtedly the case, lastly, that in the morning after a 

 wakeful night, at a time when the vasomotor system is in a state 

 of "unstable equilibrium", we find unusually great variations in the 

 number of leucocytes; as a rule also the numbers are higher. 



It is reasonable and natural from this standpoint to find, as 

 shown by Kjer-Petersen, that the number is as a rule more vari- 

 able in women than in men. 



In addition to these — we might well say "spontaneous" — 

 variations we also find others, caused by various physiological 

 changes, which in various ways alter the conditions of circulation. 

 The "statiske Leucocytreactioner", variations in the number of leu- 

 cocytes owing to changes in position, shown by Hasselbalch and 



