320 OHIO EXPERIMENT STATION: BULLETIN 214 
In the study of disease susceptibility it has been shown that 
other features being the same, the percentage of water is an index: 
thus, parts having the higher water content are attacked more read- 
ily than those with lower water content. 
With annual plants or those reproduced each year by tubers or 
seed, the opportunities to breed resistant strains are extremely good 
and the results obtained are highly promising. Physiological weak- 
ness in plants may often be translated in terms of disease suscept- 
ibility; this holds with emphasis in vegetables and grains. Apparent 
physiological vigor may arise from various causes, and when 
expressed in terms of more rapid growth or higher water content 
or succulence of the parts may be indeed a source of weakness in the 
midst of disease. Selections made for the purpose of securing 
resistance to disease are made under conditions of dzsease prevalence 
with highest promise. This field of breeding for disease resistance 
is one of fruitful promise. 
Studies in this line have been made by the Horticultural Depart- 
ment of the Station in respect to resistance of potato plants to the 
early blight disease. By selection of hills that withstood early 
blight attack and planting tubers therefrom and subsequent repeti- 
tion of this work (See Bulletin 174) early blight resistant strains 
weresecured. The differences between these strains and non-se- 
lected tubers in 1908 during the marked prevalence of early blight 
was very striking and clearly showed thata tangible resistance 
capable of reproduction has been secured. Owing to the wide extent 
of this field with vegetables and grains, much may properly be 
expected from breeding for disease resistance in the future. Much 
progress has been made with cotton resistant to wilt and with musk 
melons resistant to leaf blight. For the present other remedial 
measures will also need to be pushed. 
CONCERNING PARASITIC FUNGI 
A fungus (plural, fungi) is a plant, a member of the class called 
fungi. The fungi are low in the scale of plant life, being classed 
with the alge and other similar plant forms. They are lower still 
in the life scale than the mosses and liverworts; above the mosses 
come the fern-plants, and above these the seed plants, suchas grasses 
grains, clovers, trees, shrubs, herbs and the like, with which we 
come in contact every day. The fungi are distinguished from higher 
plants as wellas from their nearer relatives, the alge, by the absence: 
of green color, and for that reason, we may assume, by the lack of 
power to prepare their own food from the mineral substances dis- 
solved in water, and from the gases contained in the atmosphere. 
