TOXINS. 33 



chloric acid and precipitated by the addition of rock salt, after which 

 the precipitate was washed with saturated salt solution, dried at 100°, 

 and freed from salt by washing with water. Nencki designates this 

 substance as "mycoprotein," and finds that it has the formula 

 CjsH^NgOj. Freshly prepared mycoprotein forms amorphous flakes, 

 which are soluble in water, alkalis and acids. The aqueous solu- 

 tion is acid in reaction. After being dried at 100° it is no longer 

 wholly soluble in water. Nencki found that it is not precipitated 

 from aqueous solution by alcohol, but by picric acid, tannic acid and 

 mercuric chlorid ; that it does not give the xanthoproteic, but does 

 give the Millon and the biuret reactions. According to Schaffer, it 

 is changed by acids into peptons, and on being fused with five parts 

 of potash it breaks up into ammonia, amylamin, phenol (0.15 per cent, 

 of its weight), valerianic acid (38 per cent.), leucin and traces of 

 indol and skatol. A proteid obtained from the yeast plant has the 

 formula Cj^H^iNgOj. It should be understood that these formulae 

 are of but little value inasmuch as chemically pure bodies were not 

 secured. 



The pyogenetic substance obtained from the pneumonia bacillus 

 of Friedlander was found by Buchner to give the following reac- 

 tions : It is soluble in water and the concentrated mineral acids, 

 very soluble in dilute alkalis, from which it is precipitated on 

 the addition of an acid. From its aqueous solution it is not pre- 

 cipitated by heat, nor by saturation with sodium chlorid, but is pre- 

 cipitated by magnesium sulphate, copper sulphate, platinum chlorid, 

 gold chlorid, lead salts, picric acid, tannic acid, and absolute alcohol. 

 It gives the xanthoproteic, Millon and biuret reactions. 



In old bouillon cultures, the dead, disintegrated bodies of the 

 bacteria form a sediment. It is not at all probable that an analysis 

 of this sediment represents fairly the constituents of the living germs. 

 During the disintegration certain constituents of the cell pass into 

 solution, and these soluble substances are probably the most impor- 

 tant parts of the bacterial cells, so far as they are concerned in the 

 causation of disease. Similar processes undoubtedly occur in the 

 body of an animal infected with a pathogenic organism and it is 

 generally believed that these soluble substances cause the symptoms 

 of the disease and death. 



Toxins. — When it became known that some of the specific patho- 

 genic germs elaborate both in artificial cultures and in susceptible 

 animals poisonous basic substances or ptomains, it was surmised that 

 the symptoms of the disease induced by the microorganisms were 

 due, in all cases, to specific basic poisons, and chemists labored dili- 

 gently to isolate from cultures of each germ its specific toxic products. 

 These labors soon led to the recognition of the fact that the above- 

 mentioned surmise had been hastily drawn. It was found to be true 

 3 



