7 8 
F. STOWARD, D.SC. ! 
The effect such treatment might have on the storage 
qualities ol practically blight-free tubers was also investi- 
gated. The fact was demonstrated, provided these were 
mature, and their skins intact, that if the period of storage 
was not inordinately prolonged and the conditions were 
dry and airy, neither the storage nor cooking qualities of 
the tuber were seriously impaired. It will be readily re- 
cognised from what has been stated in regard to the entry 
of sulphuric acid into the tuber, that the practical ap- 
plication of tire acid treatment as a means of destroying 
the vitality of the buds depends in a great measure on 
the intact undamaged condition of the skin. At one period 
it appeared to be possible that the method would find 
application as a means of rendering tubers useless other 
than for consumption. The fact, however, that the material 
for further trial, representing for the most part tubers which 
had only recently been harvested, and comprising from 50 
to 75 % of tubers with damaged skins, rendered its ap- 
plication on a commercial scale impracticable. 
This question of the ready permeability of the skin 
of the seed tuber, which has been ravaged by the attack of 
parasitic fungi, is not devoid of interest from the biological 
standpoint. The facts, unmasked, furnish a suggestive 
basis for the investigation of the possible means whereby 
adventitious infection from organisms in the soil may 
occur. These organisms, which may ordinarily function as 
saprophytes, but which through the ready means of ingress to 
the unprotected storage tissue of the tuber may play a dis- 
ease producing role. 
It is somewhat remarkable, as the result of the ex- 
amination of a large number of such tubers, that there is 
little evidence of the possession of a capacity to form a 
protective covering of wound cork, which, as we have seen, 
is an invariable attribute of the healthy tuber. The subject 
is one which cannot well be pursued further, but must 
awmit a sufficiency of experimental evidence ; it is, neverthe- 
less, as it stands, one for the practical grower’s consideration. 
In this paper an effort has been made to describe the 
more salient characters and functions of the skin of the 
potato tuber from the various points of view enumerated, 
namely, its structure, its protective and impermeable nature, 
and its biological significance. 
The treatment of these various topics must not be 
regarded as having been dealt with finitely. In Economic 
Botany are many problems the solution of which essentially 
rests on the advances made in Plant Physiology and Plant 
Pathology. These departments of knowledge are largely 
interdependent, and are gradually becoming more so as time 
