1920] 



WALSTER—BARLEV 



Methods of tissue analysis 



hi 



The green samples were weighed and immediately preserved by 

 adding enough ethyl alcohol to make a 75 per cent alcoholic solu- 

 tion; and then boiled to arrest enzymic activity. The preserved 



Fig. 7. — Potassium series, cool house: N and P treatment of nos. 92, 94, and 100 

 same as no. 89 in fig. 3; note sprawling condition of "no potash" culture. 



Fig. 8. — Potassium series, warm house: N and P treatment of nos. 29, 32, and 38 

 same as no. 25 in fig. 4. 



material was then subjected to the method of tissue analysis devised 

 by Waldemar Koch, and modified by F. C. Koch (8). The 

 method used consisted essentially of 4 hours' extraction with hot 

 ethyl alcohol in a continuous extractor, followed by 1 hour's 



