BLOOD SERUM. 107 



had not been removed. The dilute alkaline solution was shown not 

 to have any germicidal action in and of itself. From these experi- 

 ments the above-mentioned investigators concluded that the germi- 

 cidal constituent of blood serum is an alkaline compound of serum 

 albumin. They also found that heating the serum albumin alkaline 

 solution to 65°, or higher destroyed its germicidal action, and they 

 explained this effect of heat upon blood serum and other artificial 

 solutions by supposing that the high temperature breaks up the com- 

 bination of the alkali with the serum albumin. Furthermore, they 

 found that a serum that had been rendered inactive by a temperature 

 of 55° could be regenerated, in part at least, by the addition of a 

 small amount of alkaline menstruum. 



Since Fodor and Ziintz have shown that freshly drawn blood 

 rapidly decreases in alkalinity on standing in vitro, an explanation of 

 the fact that blood serum rapidly loses its germicidal properties 

 naturally suggests itself. Emmerich and his co-workers confirmed 

 their belief in this theory by demonstrating that blood serum which 

 has been rendered feebly acid (0.67 part of sulphuric acid per mille) 

 has no germicidal action, but furnishes a good culture medium. 

 These investigators show the important r6le that the small amount 

 of alkali plays in the germicidal action of blood serum. This had 

 already been demonstrated by Fodor by quite a different line of 

 investigation. The latter found that the resistance of rabbits to 

 anthrax is markedly increased by the administration, by stomach 

 or subcutaneously, of sodium phosphate, carbonate or bicarbonate, 

 or of potassium carbonate. Low concludes that the introduction of 

 alkali into the albumin molecule increases its lability, and he cites 

 examples from organic chemistry in support of this view. Em- 

 merich and his assistants think it highly probable that only a com- 

 paratively small part of the albumin is active, and this small part, 

 they suppose, originates in the albumin of the daily food which is 

 converted into lymph cells, and by the disintegration of these it 

 passes into solution in the blood ; however, they admit that there 

 are some reasons for believing, with Buchner, that the whole of the 

 serum albumin is active. They state that it is possible, but highly 

 improbable, that the germicidal substance is not the serum albumin, 

 but some substance that is precipitated along with this by alcohol 

 and other agents. 



In 1893 Vaughan and McClintock, after reviewing the literature, 

 reported their work on the germicidal constituent of blood serum as 

 follows : 



1. The serum albumin is not the germicidal substance in blood 

 serum. Either this must be true or the experiment by which Buch- 

 ner demonstrated that an active pepsin does not destroy the germici- 

 dal action of blood serum must have been an error ; because peptic 

 digestion readily and completely converts serum albumin into pep- 



