58 MISSOURI BOTANICAL GARDEN. 
erties have been attributed to its humus acids. Thus 
Stutzer and Burri * killed cholera germs in a quarter of an 
hour with a decoction of peat. Lyell ¢ speaks of the re- 
mains of animals and men, which had been perfectly pre- 
served for many years in peat bogs. Kerner von Marilaun t 
holds that the preservation of plant parts is brought about 
in moors by humus acids. ‘+ The dead plants are saturated 
with these acids and are not resolved into carbon dioxide, 
ammonia and water, but preserve their form and weight. 
The rapidity of decay varies inversely as the quantity 
of compounds of humus acids present.’? Also «* the fact 
that fossil remains of Equisetums, Lycopodiums and 
Cycads... have reached us in such good condition, 
is explained by the presence of humus acids which are 
found so universally in peat.§ Ganong || points out that 
the scarcity of nitrogen in peat bogs is due to the absence of 
bacteria ‘* caused doubtless by an actively antiseptic quality 
of the bog water.’’ Trees and stumps have often been 
found in bogs perfectly preserved. Lyell (1. c.) speaks of - 
tree-trunks dug out of Irish bogs and used for masts, also 
of white cedar logs in New England bogs.§ Other 
instances might be mentioned, but these will suffice to 
show that the humus compounds have antiseptic and 
preservative properties. 
In the heartwood of the cypress one finds the wood 
substance being split up and destroyed. The decomposi- 
tion stops after a time, and the fungus mycelium, which at 
* Stutzer A.,u R. Burri. Untersuchungen iiber die Einwirkung von 
Torfmull...auf die Abtétung der Cholerabakterien. (Zeits. f. Hyg. 
u. Inf. Krank. 143 453. 1893.) 
+ Lyell, Sir Chas. Principles of geology 722. 
} Kerner von Marilaun, A. The natural history of plants 1: 262 (Eng. 
edit. by F. W. Oliver). 1894. 
§ Kerner von Marilaun. 1. c. 23612, 
|| Ganong, W. F. Upon raised peat bogs in the province of New 
Brunswick. (Trans. Roy. Soc. Canada ii. $3131. 1897.) 
4 Lyell, Sir Chas. A second visit to the United States 33. 1850. 
36 
