Periodical Literature. 539 



speaks entirely in favor of tarring, at the same time admitting that 

 the proceedure may be unsuitable in certain cases. 



Gatin has studied the morphological and anatomical changes in 

 affected trees under natural conditions and finds a considerable 

 stunting, with the leaves frequently wrinkled and spotted, at times 

 lacerated and falling prematurely, while the shoots of the year 

 are less vigorous, the higher parts of the crown being attacked 

 more than the exposed lower parts. Histological study shows 

 that stunted limbs of the year (Catalpa) have a cortex of the 

 usual thickness, altho the subepidermal cork layer is much better 

 developed. The endoderm is not specially differentiated, while 

 the central cylinder is much smaller. The medullary rays are 

 scarcely noticeable and the pith cells are small. October branches 

 are almost devoid of starch, while sound ones are richly supplied. 

 A study of flower stalks yields similar results. 



In the case of Pelargonium, Sycamore Maple and Aesculus the 

 plant reacts by cork formation on leaves. 



Experiments to determine the relative importance of vapor 

 versus tar dust particles were carried out on several species of 

 trees and shrubs by dusting the leaves in the evening once a week 

 from July i to 18, then two to three times a week up to September 

 15, in every case preceding the operation with a light sprinkling. 

 All the trees were affected, the injury varying from a browning, 

 or perforation, of the leaves to a stunting of the young branches. 

 These results contradict the experiments of Mirande noted above. 



Mirande, M. De Faction des vapeurs sur les plantes vertes. Compt. Rend, 

 Acad. Sci. Paris) Aug., 1910. Pp. 481-483. 



Mirande, M. Les effets du goudrounnage des routes sur la vegetation. 

 Ibid. Nov., 1910. Pp. 949-952. 



Griffon, E. InAuence du goudronnage des routes sur la vegetation avoisin- 

 ante. Ibid. Dec, 1910. Pp. 1070-1073. 



Gatin, C. Influence du goudronnage des routes sur la vegetation des 

 arbres du hois de Boulogne. Ibid. July, 191 1. Pp. 202-204. 



Gatin, C et Fluteaux Modifications anatomiques produites, chez certains 

 vegetaux, par la pouissiere des routes goudronnees. Ibid. Nov., 191 1. 

 Pp. 1020-1021. 



Gatin, C. Reproduction experimentale des effets du goudronnage des 

 routes sur la vegetation avoisinante. Ibid. Oct., 191 1. Pp. 688-690. 



