DANIEL'S EXPERIMENTS AND CONCLUSIONS 



161 



The conditions of success of grafts are of two kinds, extrinsic 

 (conditions independent of the nature of the plant as soil, tem- 

 perature, etc.) and intrinsic (conditions dependent upon the 

 peculiar nature of the plants grafted, as method of cicatrization, 

 analogy and botanical relations. The extrinsic conditions neces- 

 sary to observe by approach are : 1, A temperature suf- 

 ficient to produce primary tissue; 2, prevention of all conditions 

 which cause rotting or drying of the cicatrized meristem (pri- 

 mary tissue) ; and 3, maintenance of adherence of the wounds by 

 the aid of ligatures susceptible of being loosened progressively 

 with the growth of the plant. 



211. Cicatrization. Plants cicatrize 

 their wounds either by simple drying 

 of the cut tissues and neighboring 

 cells or by regeneration of tissues by 

 the aid of the primary tissue. All 

 methods have failed with the mono- 

 cotyledons and cryptogams experi- 

 mented upon. Hence Daniel concludes 

 that grafting by approach is impos- 

 sible with plants that cicatrize their 

 wounds by desiccation of the wounded 

 cells and neighboring tissues ; i. e., are 

 incapable of regenerating tissue. 



In order to learn whether only 

 plants with cambium may be grafted, 

 as generally believed, Daniel worked 

 with many monocots and cryptogams 

 and secured a perfect cicatrization by 

 the tongue graft with gladiolus, day 

 lily (Funkia cordata), Caladium, white 

 lily (Globba coccinea) and several 

 others, even with one of the club 

 mosses (Selaginella arborea) . The 

 success of these grafts shows that 

 grafting by approach is possible 

 with certain monocots and that the 



presence of the cambium layer is not always necessary to the success 

 of all grafts by approach. 



212. Analogy. The difference in hardness and the histological 

 nature of woods may not be an obstacle to anatomical union. A 

 natural, distinct cicatrization occurred 

 between grafted oak and beech, and 

 between fir and linden, oak and ash 

 united by their stems and oak and 

 walnut by their roots. Rose and grape 

 have also been united. Nevertheless, 

 the graft by approach does not always 

 succeed between plants so different- 

 Daniel tried in vain to graft horse 



FIG. 



137 GRAFT WRAPPING 



MACHINE 

 A great time saver 



FIG. 138 GRAFTERS' OR 

 BUDDERS' KIT 



Tools, cions etc., are carried thus. 



chestnut on common chestnut. 



