71 



terial wliich i)reveiits the development of smallpox. Now what is a 

 serum? A serum is a sap or fluid of an organism containing defense 

 material which has been brought out by a vaccine which wias introduced 

 for that purpose. In botany a serum would have to be a sap from a 

 plant that contained defense material. There is great significance in 

 the fact that when the top of Dr. Zimmerman's tree was sawed off the 

 tree died. Why.^ It is the top of the tree that manufactures defense 

 material, as well as food for the plant. Tlie top was busily engaged 

 in making material for defense. 



Dr. Zimmerman savs no tree has natural immunity. I would dis- 

 pute that j)oint because relative immunity, at least, must exist in order 

 to protect a tree against bacteria and fungi which attack it whenever 

 it is wounded in any way. Some of the chestnut trees have a relative 

 degree of immunity to blight while others are highly vulnerable. 



Dr. Zimmerman: I still believe that a tree does not liave natural 

 immunity. 



Mr. Spencer: As far as I know there is no blight in Illinois. 



The Secretary: There may have been some blight in the Riehl 

 orchard but there is none there now. It has been burned up. I do 

 not think we need to worry about the blight in Illinois. We do not 

 have the same situation as in the East where there are immense forests. 

 Pathologists are working on the condition all the time. 



Dr. Thiess: Years ago I bought from Mr. Riehl a chestnut wliich 

 he called the Paragon, whicli he said was highly resistant to blight. It 

 has been growing in my orchard two years and there is not the 

 slightest blight on it though we have blight all around it. 



]Mr. Ellis: I find of the varieties sent out the one I ffot from 

 Illinois the most blight resistant of any I have seen. 



Mr. Bixby: That is the variety that has done the best for me. 



Mr. Ellis: I would like to ask Mr. Bixby if he knows whether 

 Mr. Endicott is in the business of selling chestnuts. 



The Secretary: Mr. Endicott does not sell chestnuts. 



Mr. Ellis: There are some nurserymen there that had chest- 

 nuts for sale and also some other nursery stock. 



♦ 



