68 BOTANICAL GAZETTE [yuLy 
_ On the other hand, what is the origin of the pigment? Itisa 
general observation that wounds inflicted on the tissues of the sorghum 
developed a red coloration around the injured part. It is important 
to understand precisely in the preceding experiments the role of the 
local lesion induced by the inoculating needle. Aseptic punctures in 
the pith of healthy sorghum stems were made under conditions identi- 
cal with those of the preceding experiments, the inoculating fluid alone 
being omitted. Under these conditions the pigment appeared in the 
wounded cells, but it was not abundant and was rigorously confined to 
the wound. The quantity of coloring matter thus produced is not 
capable of being carried by the bundles and of spreading beyond the 
actual point of the lesion. The experiment shows, however, that the 
chromogenous property belongs to the wounded cells of the sorghum. 
From the preceding facts it may be concluded : 
1. That yeasts may develop in the living cells of the sorghum. 
2. That the parasitism of these yeasts may bring about an intensé 
red coloration of the plant tissues, this coloration being the same 4s 
that which may be observed in the disease of sorghum called the blight. 
The production of the pigment appertains to the affected cells, and the 
parasite takes part only through the lesion which it produces. 
_ These results confirm the old hypothesis of Palmeri and Comés, — 
who, observing the fermentative phenomena of the red juice of the 
pith of the blighted sorghum, had inferred from it the parasitic action 
of the Saccharomycetes without giving it experimental proof. € 
same facts, moreover, are not contradictory of the experiments of Bur: 
rill, Kellerman, and Swingle. In fact, it may be concluded that, the 
ted coloration being the result of a chromogenous function character 
istic of the wounded cells of the plant, different parasites, yeasts 
bacteria, may, by developing in the tissues, induce by continued lesio® 
the production of a considerable quantity of the pigment. 
_ On the contrary, it is necessary to make complete reservations * _ 
to the conclusions of Bruyning, who, attributing to the bacteria them 
selves the chromogenous function, denies to all micro-organisms 1ac¥ 
ing this function while outside the host plant the power of inducing the | 
aes of sorghum blight.—Maxime Ranals, School of Pharma), ~ 
aris. 
