Periodical Literature. 755 



able for the growth of Merulius, while the uncooked blocks only 

 supported a scanty surface growth. After three weeks it was 

 estimated that the development was three times as strong as on 

 the uncooked wood. The water-extract from the wood was found 

 to be toxic when mixed with gelatin media or dextrose solution. 

 By boiling spruce wood in a 2% tannin solution it was practically 

 rendered immune. 



The toxic action of tannin and gallic acid toward Merulius is 

 specific, depending on the particular kinds of these substances and 

 not upon the acid reaction, the former being only one-tenth as 

 acid as the latter. As to the relation between the constitution of 

 tannin and its toxicity little can be said until we know more of 

 the specific chemistry of the organisms under consideration. In 

 the present case if we do not wish to explain the immunity of oak 

 as due to an essential difference in fungus enzymes, we can ascribe 

 it to the unfavorable action of tannin. As is well known, inhibit- 

 ing substances are often disposed of by fungi through cleavage, 

 oxidation or reduction, and it is very possible that the general 

 conditions of temperature, constitution of media, concentration, 

 etc., are of essential importance, so that Merulius, under particu- 

 larly favorable conditions, might do the same with tannin. 



The pigment production of Merulius lachrymans is considered 

 in a second paper by Wehmer. The earlier investigators attribute 

 it to certain distributing factors, such as poor nutrition, too high 

 temperature, etc. By varying the composition oT the nutrient 

 solutions and the consistency of the solid media Wehmer sought 

 to follow up the question, but without arriving at any definite 

 conclusions as to the specific causative factors. Shades of color 

 varying from bright yellow to reds and browns were secured. 

 Although, in general, the kind of nutrient is not the determinant it 

 still seems to play a part. The bright brown spore pigment is 

 soluble in alkaline reagents with a blackish-brown color and can 

 be precipitated from dilute sodium hydroxid. 



Der wachstumhemmende EinAuss von Gerbsduren auf Merulius 

 lachrymans in seiner Beziehung zur Resistens der Bichenholzes gegeii 

 Hausschwamm. Mycol. Centralbl. 1:138-148, May, 166-174. July, 1912. 



Uber Pigmentbildung bei Merulius lachrymans Schum. Ber deutsch. bot. 

 Gessell. 30:321-329, 1912. 



