ADAPTATION. 19 



way, and often when the chlorosis is very intense the 

 extremities also dry and fall off. 



Although being very yellow, the shoots continue to in- 

 crease, but more slowly, and produce new leaves, but, as the 

 green surfaces which alone elaborate the matters necessary 

 to the nutrition of the various organs of the plant are 

 altered, the new leaves always remain small and yellow. 

 Numerous small shoots, always very short and slender, with 

 rudimentary leaves, spring from the axillary buds, and the 

 vine then presents a bushy and stunted growth. This form 

 of chlorosis is c lied cottis * 



If the disease takes place before the vine blossoms (and it 

 is almost always the case), it brings about non-setting of the 

 flowers, and retards the maturation of the berry, which 

 remains small, miller ande, yellowish with a few brown 

 spots, and later on dries off. 



The roots have a normal or weak development; they do 

 not show any outside alteration ; nothing indicates that they 

 belong to a diseased vine, and a section does not show any 

 internal lesion of the tissue. However, they are softer and 

 more flexible than the roots of healthy vines, bending like 

 india rubber, and are less lignified. They contain little or no 

 reserve matters, except perhaps the larger ones, no reserve 

 of starch in the cells after the wood has become lignified. 

 The contents of the regions in a state of active life (genera- 

 tive layer, etc.) are very deficient in portoplasm. The fibro- 

 vascular bundles and cells of the liber are almost empty 

 in a word, there is a lack of nitrogenous matters and car- 

 bohydrates. In the branches there is an absence of the 

 same matters as well as in the leaves and all the herbaceous 

 organs. 



In the leaves, not only has the chlorophyll disappeared, 

 but also its sub-stratum, the chlorophyll corpuscles. However, 

 in the chlorotic branches the chlorophyll does not disappear 

 as early as in the case of the leaves; there is still some 



* The disease which Dr. J. Guyot described in the Charentes under the 

 name of cottis, is totally unknown there. The word cotti is an adjective, not a 

 noun. One says a cotti fruit, a cotti branch, to designate a fruit or branch 

 altered by any cause (insect larva, bruise, etc.), or bearing lesions similar to 

 those resulting from a blow. A branch attacked by anthracnosis is cotti at the 

 point where the canker shows, and by extension a plant is cotti when it presents 

 any deformation. The actual cottis has been characterized in the South of 

 Prance; it is known in the Charentes since the American vines have been cul- 

 tivated there. The name is an adjective changed into a noun by Dr. Guyot 

 and the vine-growers of the South. 



