( 629 ) 



justice to ha\e within some hours the certainty whether bloodstains 

 appearing on an object, originate from human blood (in our countrj 

 of course monkey blood may as a rule be left unconsidered). 



It is now indeed possible to show the presence of human blood 

 (resp. of the monkey) in older stains with the aid of the catalase of 

 the blood. I wish to draw the attention to this that the presence of 

 blood must have been proved by a preceding microscopical, chemical 

 or spectroscopical investigation because other fluids of the body too 

 (sperm and milk) cause a reaction of catalase. 



The method of investigation is simple. If the dubious blood trace 

 is dried on some tissue, a piece of it is extracted with water at the 

 ordinary temperature and the extract is divided into two parts. One 

 part is mixed with a solution of hydrogenperoxide of I'/o fi'id the 

 mixture is put into a fermentation tube. The other part is heated 

 for half an hour in a watei-bath at 63°, then cooled down to 15° 

 and after having been mixed with a solution of HjO, it is also put 

 into a fermentation tui)e. If within some hours oxygen develops in 

 both tubes, it may be concluded that human — (resp. monkey-) 

 blood is present ; the quantity of oxygen in the second tube is of 

 course smaller than that in the first. When active catalase of the 

 blood is present the splitting off of oxygen begins soon after the 

 mixing, and is finished in some hours. 



If however only in the first tube oxygen is split olT and the 

 second tube does not show any development of gas, it follows that 

 the catalase of the blood has become inactive by the heating to 63° 

 for half an hour, and that the dubious blood does not originate 

 from man or monkey. 



I was in the opportunity of applying these experiments to fresh 

 bloodstains of man, dog, ox and horse and to bloodstains on linen 

 from the year 1903 originating from man, oxen, horses, goats and 

 pigs. The old bloodstains gave the same results as the fresh blood. 



If we dispose of more bloodstains we can follow the process of 

 the reaction somewhat quantitatively by preparing for instance a 

 larger quantity of extract with water, dividing this in parts of 5 cM.', 

 heating this to 63° during different periods in test-tubes and mixing 

 it with HjOj and titrating it, as has been communicated in the 

 preceding paper. The peculiar process of the reaction, graphically 

 expressed, does not give a representation of the absolute quantity 

 of the catalase of the blood which is present, but is so characteristic 

 that human- (and monkey-) blood c<an be easily distinguished from 

 that of another species of animal, even in the dried state. 



44 



Proceedings Royal Acad. Amsterdam. Vol. VIII. 



