476 



acids, and oleic acid have, but tiiat a very small fraction is present 

 which acts in the plasma as would do linolenic acid. Addition of 

 fatty acids extracted from blood lowers the surface tension of serum 

 from 53 dynes to 49,5 dynes; when more extract is added, the 

 tension remains as constant as if oleic acid were added. The extracted 

 fatty acids lower the surface tension of the serum to that of total 

 blood, for corpuscles also can decrease the surface tension of serum 

 to 50 dynes. So the tension of blood is not decreased by extracted 

 fatty acids. If it may be concluded, that a small fraction of highly 

 unsaturated fatty accids is absorbed normally to the corpuscles, this 

 must be verified by further investigation. 



In a following communication we will describe the intlueiice 

 which the investigated mechanisms of inactivation have on normal 

 and pathological haemolysis. 



S Ü M M A R Y. 



By means of determination of surface tension of blood and 

 serum it was shown, that the normal fatty acids of the blood or 

 also those added on purpose are bound in the form of Calcium 

 soaps, by which mechanism their capillary activity is decreased 

 considerably. It is very |)robable, that this formation of a Calcium 

 compound is the cause of disappearance of haemolytic properties of 

 stearic acid, palmitinic acid and oleic acid in serum. The inactivation 

 by means of Ca is not present in the case of linolenic acid; by 

 this cii'cumstauce the haemolytic character of this substance of serum 

 will be much greater. 



III. Experimental anaemia caused by injections of linolenic acid. 



In a previous communication it was pointed out, that higher fatty 

 acids in the blood generally are circulating as Ca compounds, and 

 thus have lost their marked capillary activity. It was stated however, 

 that the Ca soaps of the higher unsaturated fatly acids i.e. of 

 linolenic acid, do not loose their capillary activity, and that hy this 

 reason we have to expect much greater haemolytic action in vivo 

 of this substance. 



It was shown, that linolenic acid is an intravital haemolytic 

 substance, of great activity and that there is no direct inhibition of 

 the action of linolenic acid in the plasma. It was known for a long 

 time, that injection of the saturated fatty acid or of oleic acid can 

 not cause a distinct intravital haemolysis, probably by the mechanism 

 of Ca inactivation, described formerly. In the case of linolenic acid 



