814 FRUIT CULTURE IN FOREIGN COUNTRIES. 



an exaggeration, as I have seen vines planted in very moist lands (the water re- 

 mained on the surface from October to Jnne, and the culture vas impossible, save at 

 rare and short intervals) that never grew yellow ; and I have more than mere doubts 

 about the part that moisture plays in turning the leaves yellow. 



Indeed, the stains of chlorosis which at times are noticed in the vineyards in ques- 

 tion are always on the hillsides, where water never remains and where the soil and 

 subsoil are neither too moist nor too dry. Besides, the chlorosis is never very dan- 

 gerous which can be attributed to excess of moisture. It appears chiefly in the 

 spring, and in the course of vegetation it disappears. 



The influence of drought is equally great. I have often noticed vines that were 

 planted in very dry land. After a few days of sun and a slight breeze to dry the 

 land entirely, the leaves fade .-md the grapes wither and fall, but no chlorosis. 



As for the alternatives of drought and moisture, these seem to be the natural con- 

 ditions of vegetation. Under this hypothesis, calcareous lands absorb much water, 

 then rapidly dry ; at first drowning the roots, then leaving them completely dry. The 

 chalky lands in the vicinity of Cognac do not swell with water, and a few hours after 

 rain they can be easily worked. They do not dry up either. We have never observed 

 vines suffer from chlorosis, although it is in such lands as these that chlorosis is most 

 intense. 



Iron seems to play a certain role In the formation of the green matter of the leaves; 

 some have even supposed that the yellow color might be owing to this element in the 

 soil ; but this is not so. For a long time past it has been remarked that the white 

 soil (where this cause is chiefly placed) is as rich in iron as highly colored lands. 



This metal, it is true, is not found there in the same state of oxidation and of lia- 

 bility to assimilation ; but it matters little, since the roots which grow in the white 

 soil contain as much iron as those growing in soil very rich in color. Besides, most 

 of the land of Groie in the Charentes where American vines do not thrive is the 

 most highly colored, the soil being very red, and consequently ought to contain more 

 oxide of iron in the best state to assimilate. 



It must, however, be said that an addition to the soil of a solution of sulphate of 

 iron poured at the foot of the roots has a happy action on the formation of the green 

 matter of the leaves. This is the result obtained from numerous trials made in land 

 of Groie * by Mr. Jord in the Charente-Iuf^rieure. The same result I have myself 

 obtained from experiments made in laud of Champagne. But this action of sulphate 

 of iron is very limited; the vines thus treated are a little less yellow, that is all the 

 difference. 



The slight overheating of the soil, which results from want of coloring on the sur- 

 face, does not account for the greater part of cases of chlorosis. The lands of groie, 

 it has already been stated, are colored red or ocher ; the heating of the soil is almost 

 too intense. The greater part of the land of Chanipagne has a, deep gray, or even 

 black color, like marsh-land. 



The same may be said of the pretended influence of light, which, according to some, 

 is one cause of chlorosis when it is not intense, and according to others when it is ex- 

 cessive. 



As for the climate, it surely plays a certain role in the adaptation ; but generally 

 speaking, the more it is soft, temperate, and, above all, less burning, the more it fa- 

 vors the development of American vines. And this is so true that in the south of 

 France the Riparia rupestris and Jacc|uez solonis are almost the sole vines cultivated 

 as graft bearers, while less-heated regions cultivate many more. 



The Vialla, which does not grow badly in the south, vegetates here very well, and 

 equally well in the Beaujolais. It is quite the best for light lands that are silicious. 



The Herbemont, that turns yellow so rapidly and is stunted in the Herault, thrives 

 in analogous soils of the Charentes, and even in bad soils it grows vigorously. The 

 same is true of the Oporto, York Madeira, etc. It is clear that the phyloxera makes 



* Groio: Light, yollow soil, mixed witb ohalk-stoneB. 



