ROUND TABLE DISCUSSION 221 



media are known in which lengthy survival is possible, but there 

 is usually no growth. 



Harpaz: We were recently contemplating an extraction of 

 haemolymph from insects with a view of separating the haemo- 

 lymph cells and growing them in culture. Should this succeed 

 we might also have a suitable material for dormancy studies. 

 Some of these cells are fairly large and can be studied with the 

 ordinary light microscope. We could get about a couple of 

 milliliters of material from a fairly large insect. 



Kindler: Bearing in mind Prof. Shulov's suggestion that lack 

 of movement is a sign of dormancy in insects, might it not be a 

 good idea to use muscle tissue? 



Lees: There would be no technical difficulty. You could 

 dissect the muscle tissue free from anything else, except hemo- 

 cytes from the blood. However, the muscle tissue of an insect 

 in diapause may not show any characteristics peculiar to the 

 diapause condition. In the Cecropia silkworm, the muscles 

 contain their full complement of enzymes and are still fully 

 functional; thus the insect is able to wriggle its abdomen. 



Galun: Even if we did succeed in getting a tissue culture, it 

 would be no benefit for the study of this aspect of dormancy. 

 The concept of diapause does not apply to the cells once they 

 have been removed from the regulatory system of the body. 



Moderator : Perhaps we should not take so extreme a view. It 

 should be remembered that in the mammalian system it was for 

 a long time generally thought that no hormone effect could 

 operate outside the intact organism. Yet this is no longer so. 



Galun: No, I assume some hormone effect could be obtained, 

 but not in the case of arrested growth. 



Moderator: What is the position in this regard as to fungi? 



Wahl: I am afraid that it will be extremely difficult to find 

 among fungi genetically pure and uniform material for dor- 

 mancy studies. 



Nachmony: a liverwort which I have been working with 

 might be a particularly suitable test object. In this organism, one 



