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the second contained pale red serum and spectroscopic oxyhemo- 
globin. After 24 hours the broth in the test tube Il was decidedly 
turbid after slight centrifuging to remove the erythrocytes; the broth 
in the test-tube I was clear. Both proved to be sterile. 
The question has still to be answered, what may be the cause of the 
turbidness. If one adds a little more hemoglobin-solution to the broth 
and leaves it in the incubator, the next day a turbid liquid and a 
red precipitate are obtained; the latter does not dissolve, or only 
with great difficulty in acids, but easily in diluted alkalies. The 
solution does not show absorptionbands in the spectroscope; in 
adding a little ammonium sulphide, we get directly a distinct band, 
characteristic of hemochromogen. If we first add potassium cyanide, 
and then ammonium sulphide, we get two bands, of which the left 
one has moved a little towards the red in comparison with the 
above band. All this points to the fact that we were dealing with 
hematin. 
It is obvious that we have an autolysis of the hemoglobin. In 
most cases the globin will remain dissolved, as the broth is not 
exactly neutral; in neutral salt solution it may add however to the 
turbidness. If one wants to obtain the turbidness of hemoglobin in 
salt solution, one ought to take highly diluted hemoglobin solutions, 
otherwise it does not appear. This happens, because the reaction 
of the salt solution changes by adding a great quantity of hemo- 
globin solution. 
The fact of getting turbid at 37° C. of tubes of broth and blood 
that has been drawn from the body a considerable time ago, a well- 
kown fact to those, who experiment with this cultureliquid, depends 
of course on the same fact: autolysis and the formation of hematin. 
Recapitulating the facts, we may say that the turbidness of broth, 
described by Von ANGERER after adding the filtrate of the blood of 
serious influenza patients, is not specific, but must appear every where, 
where in the blood an important destruction of erythrocytes has 
taken place. The turbidness is not a virus, but hematin (and globin) 
originating from the hemoglobin present. 
Laboratory for hygiene of the University. 
Amsterdam. 
