110 GERMICIDAL PROPERTIES OF BLOOD SERUM. 



found that on removal of this precipitate the solution became inac- 

 tive. Lowit ' rubbed up isolated leucocytes with pulverized glass 

 and extracted from the powder thus obtained a bactericidal sub- 

 stance which is not destroyed or even weakened in action by five 

 minutes' boiling. The germicidal extract thus obtained is cloudy, of 

 feebly alkaline reaction, gives the biuret test, contains but little 

 proteid which is precipitable by heat, and yields a flocculent precip- 

 itate on the addition of acetic acid. From their investigations both 

 Bail and Lowit conclude that the heat-resisting bactericidal substance 

 obtained by them is nuclein or nucleinic acid or a derivative of one of 

 these substances. Schattenfroh ^ combats the conclusion reached by 

 the above-men^oned authors. He claims that the germicidal sub- 

 stance obtained by Lowit consists of sodium silicate extracted from 

 the powdered glass, and he attempts to demonstrate this by an ex- 

 periment in which the germicidal action of this compound is tested. 

 This experiment, however, is not convincing, inasmuch as it shows 

 that even a one per cent, solution of sodium silicate is practically 

 without bactericidal properties ; and it is not probable that water or 

 physiological salt solution will extract from glass a stronger solu- 

 tion than this. In his criticism on the work of Bail, Schattenfroh 

 admits that the results obtained by his opponent are exactly what 

 he himself observed, but he thinks that in this case the heat-resist- 

 ing germicidal substance is the alkali used in extracting the leuco- 

 cytes. This criticism also is somewhat far-fetched inasmuch as 

 Schattenfroh attempts to demonstrate the truth of his assertion by 

 showing that Bail's extract, when neutralized or rendered feebly 

 acid, is without germicidal properties, but everyone knows that 

 blood serum when neutralized or rendered feebly acid also becomes 

 inactive. Moreover, Fodor long ago demonstrated that increasing 

 the alkalinity of the blood increases its germicidal properties. 

 Schatten&oh's own investigations have demonstrated that a tempera- 

 ture of 56° to 58° does not destroy the alexins in aqueous extracts 

 of isolated leucocytes. On this point he makes the following state- 

 ment : " Experiment 3 and others leave no longer room for doubt 

 that the bactericidal action of leucocytes is retained after being 

 heated in distilled water for half an hour to from 55° to 60°. It 

 may be seen from what has been stated that the resistance of the 

 alexins to heat is largely dependent upon the nature of the menstruum 

 in which they are dissolved or held in suspension." 



The evidence concerning the manner in which the leucocytes pro- 

 duce alexins is scarcely more satisfactory than that bearing upon the 

 influence of temperature upon the latter. Hankin ' was probably 

 the first to suggest that the alexins are products of the amphophil 



^ZUgler's BeitrSge, 22. 

 'Archivf. Hygiene, 35. 

 ' GentrcUbUUt f. BakierioUxfie, 12. 



