ADAPTATION. 33 



in nitrogenous matters and carbo-hydrates. The chlorophyll 

 disappears first, and new chlorophyll corpuscles are not 

 formed; consequently, the matters absorbed by the roots are 

 not elaborated any longer by the green matter which has 

 disappeared ; or they are imperfectly elaborated by an insuf- 

 ficient quantity of badly-developed green matter. 



Whatever the case may be, although the question has not 

 been sufficiently elucidated, carbonate of lime is the true 

 cause of chlorosis.* 



Can the other salts of lime cause chlorosis? They have 

 not all been studied from this point of view; however, in 

 practice, we need not be pre-occupied by most of them. 

 Sulphate of lime (gypsum) alone is found to a certain 

 extent in some vineyards. It does not seem that it has 

 the power of rendering the vine yellow. The study made 

 by Chauzit of certain vineyards planted in gypseous land 

 shows that chlorosis is only found when the gypsum exists 

 side by side with carbonate of lime. One of us has 

 cultivated American grafted vines in artificial soils con- 

 taining 55 per cent, of sulphate of lime. The vegetation 

 is stunted under these conditions ; the vine after developing 

 normally at the start, stops and remains weak, and although 

 this circumstance is favorable to the appearance of chlorosis 

 they have always remained green. 



But from what has been said, one must not conclude 

 that analysis will always give the measure of the effect of 

 carbonate of lime on the vine. Its action may be 

 modified by different circumstances, and increased or 

 diminished very sensibly. It is, firstly, dependent not 

 only on the quantity of carbonate of lime in the soil, but 

 also on the distribution of this substance amongst others: 

 sand, clay, etc. : and two soils equally calcareous may present 

 from this point of view marked differences. If, in a given 

 soil, the carbonate of lime is disposed around grains of 

 siliceous matter (calcareous sandstone, tertiary sands 

 surrounding Montpellier. etc.) ; the vines will become much 

 more yellow than in the case of another soil where the 



* Amongst white soils the exterior aspect of which is identical with that of 

 chalky soils, and which might, perhaps, have an action as a cause of chlorosis, 

 are the dolomitic soils (carbonate of magnesia) and the gypseous soils (sulphate 

 of lime). 



American vines have been cultivated with success in the dolomitic soils of 

 the Gard (Bajocien, Bathonien and Infralias). It has been noticed that in 

 soils containing up to 42 per cent, of carbonate of magnesium (Chauzit Jean- 

 Jean, Desjardins) the American vines, even the Riparias, throve. 



