THE JOURNAIv OF PHARMACOLOGY. 243 



had long before been carried on. He did not know the history of the 

 shrubs, but in the following weeks, which I devoted largely to the study 

 of coca plantations, I found a number of places such as I have described 

 above. Forests had not re-covered the plantations, but shrubbery had, 

 and amidst this shrubbery, occupying the old terraces, were numerous 

 plants which the natives assured me, though the fact was too evident to 

 require it, represented the original coca stock run wild. The changes in 

 the leaves were most marked. They had greatly increased in thickness 

 and in the strength of the venation, which was strongly impressed upon 

 the upper surface. This surface had become much darker and more shin- 

 ing than in the cultivated leaves. The lower surface was brown and 

 roughened, and the lateral lines, so characteristic of the cultivated form, 

 had become obscure or even entirely wanting in many leaves. In others, 

 their " areola " was outlined by a different color and surface, and enclosed 

 by irregular lines consisting of connected veins, but there were no lines of 

 collenchyma tissue, while in still others, one or both of these lines ran for 

 a part of the way. I^astly, and most important, the leaves had become 

 strongly pointed, in some distinctly acuminate. These changes are not 

 surprising, in view of the results of recent experiments upon changes in 

 leaf form produced by modifications of environment. However, a discus- 

 sion of this question is not called for, as theories and explanations must 

 accommodlves toate them seknown the facts. 



In Fig. 4 the leaves are thicker than in any of the others, while there 

 is little tendency toward the ovate form. In another specimen not figured, 

 the thickness and roughness are not quite so great, the areola or lateral 

 lines, or both, are plain, though not conspicuous, in some leaves, wanting 

 in others, and the ovate acuminate form is distinct. In Fig. 5 the last 

 mentioned character is very marked indeed, the plant being the equivalent 

 of that of Mathews (Fig. 2). Lateral lines or areola are visible in most of 

 the leaves of this specimen, but not at all of the same character as in the 

 cultivated leaves. I have not had an opportunity of examining flowers 

 of these wild specimens, but I have many in fruit, and this agrees exactly 

 with that of the cultivated form. 



It must be borne in mind that the thickening, roughening, change of 

 color and loss of lateral lines here referred to, pertain only to sun-grown 

 plants. When grown in the shade, different changes occur, as shown 

 below. It might be added that other pointed-leaved specimens to which 

 Dr. Morris refers, and which I have myself studied at Kew, were also sup- 

 posed to have come from wild plants. The positive history of my own 

 specimens is thus confirmed by these bits of evidence. 



These changes in the sun-grown wild leaf may now be contrasted with 

 those occurring in leaves grown in forest shade, as illustrated by compar- 

 ing Fig. 6, taken by myself in the borders of forests surrounding the 



