54 THE ROYAL SOCIETY OF CANADA 
lary rays are formed, often twice the number that are formed in the 
normal wood. 
“Resin canals, which are absent in the normal wood of Abies bal- 
samea, are always present in the tumor, and are nearly always present 
in the wood of the older diseased branches above the tumor.” As 
there is an abnormal amount of food present in these cases, the quota- 
tions are self-explanatory. Jeffrey, in an article on the traumatic ray 
tracheids in Cunninghamia sinensis (14 A, 595), records the following 
very pertinent observation. “It is to be noted that the wound-cap is 
characterized by a considerable increase in the number of medullary 
rays present over that found in the normal wood. . . . . . The 
amount of wood parenchyma is also abnormally large in the region of the 
wound cap. Sections from the opposite side of thestem are characterized 
by a more normal amount of wood parenchyma and a normal number 
of medullary rays.” It is evident from the above that there is a close 
relation between the medullary ray elements and the wood parenchyma 
elements, the number of both depending largely on the amount of food 
presented to the growing tissues at any particular point. Whether these 
elements will form an aggregate of cells capable of containing an inter- 
cellular passage or canal depends largely on both the rapidity of growth 
and the quality of the tissues in which the increased growth occurs. 
This is illustrated by the fact that in the same growth ring there can be 
present both large aggregates of parenchyma cells without any passages 
and aggregates of cells containing such passages. The essential feature 
that the traumatic phenomena in Cunninghamia emphasize is that 
wherever there is an unusual amount of food presented to the formative 
tissues in any of the Coniferæ an increase in the number of parenchy- 
matous elements occurs, whether these elements be designated by the 
terms medullary ray cells, resin cells or wood parenchyma cells. 
Lamarliere (18) gives the following observations of interest in 
regard to the effect of certain fungi on the tissues of the common juniper. 
In the normal plant the rays of the secondary cortex consist of from 
four to six cells as seen in tangential section and are strictly uniseriate. 
The number of elements separating two rays tangentially is usually 
from six to ten. In the specimens attacked by the fungus, however, a 
great difference is evident. In the first place there is a great increase 
in thickness in this region. This is accompanied by profound changes 
in the character of the medullary ray. The cells constituting the ray 
are now much larger and very irregular in their disposition, the number 
of elements separating two rays being now two or three and often only 
one. Again, the rays are much higher being twenty-five or fifty cells 
in height or even more and frequently two-seriate. 
