ADAPTATION. 37 



vines, are in reality the most unfavorable, while the sides 

 of the hills, which drain well and seem poorer and more 

 calcareous, bear less chlorotic vines. 



This explains also the beneficial effect of drainage, of deep 

 trenching, and of all operations tending to diminish the 

 amount of water in calcareous soils.* 



This enables us to interpret the results obtained by Foex 

 and Millardet, already mentioned above. It is that inde- 

 pendently of the excellent conditions given to the root 

 growth by warm soils, soils which easily become hot are 

 generally also the driest. 



Finally, the variation in intensity of chlorosis with the 

 age of the vine and the season are not due to any other 

 causes than those above studied. But can one explain the 

 way in which they are produced? How is it that the 

 influence of lime on the young plant does not manifest 

 itself in the spring of the first year after planting out? It 

 is that at the start the vine cutting or rootling mainly 

 lives upon reserve matters accumulated in its tissues and 

 the living cells, still almost normally constituted, resist 

 longer the persistent action of carbonate of lime. But the 

 latter supervenes eventually, and in September the leaves 

 become yellow, and, working under difficulties, do not ac- 

 cumulate in the tissues of the trunk and root a sufficient 

 quantity of reserve matters. The following spring, the first 

 development takes place with the aid of this small quantity 

 of reserve matters: hence, a more intense yellowing, which 

 is, so to speak, the evolution of that of the previous year. 

 The lime having at this moment, for reasons we have 

 already made clear, a very great action, the yellow colour 

 becomes more accentuated. Then with the fine weather, 

 during June and July, a disappearance of the humidity of 

 the soil places the vine in better condition for vegetation; 

 the green colour returns, the leaves regain their normal con- 

 dition, and assimilate and elaborate the reserve matters. In 

 the spring of the following year, the active cells, well con 

 stituted owing to the reserve matters which are in greater 

 proportion than in the previous year, resist longer the 

 effect of the carbonate of lime. That is why chlorosis is less 



* If chlorosis has been attributed to humidity and compactness of soil, it is 

 because one had not been able to distinguish between clay and clay-calcareous, 

 or marly soils. In the first, chlorosis never occurs; in the two second, chlorosis 

 is due to lime, the effect of which is increased by the water contained in such 

 soils 



