326 
to 1 in. below the soil surface. After the moculations and 
wounding of the control plants when necessary, all the tins were 
kept in dne place out of doors. During the ensuing peried when 
the plants ‘were under observation, the rainfall amounted to 
6-79 in. distributed very evenly over forty days. 
The Nigella plants, both wounded and unwounded, were the 
first to show signs of disease; the typical sickly appearance was 
noticed after six days. Complete collapse ot the first diseased 
plants took place after twenty days. Meanwhile, the carnations 
and Delphiniums began to wilt, the periods between first signs of 
disease and death ranging from fifteen to eighteen days. All the 
inoculated plants of all three species were dead in thirty days. 
o difference could be detected between the behaviour of wounded 
and that of unwounded plants. Removal of dead plants from the 
soil disclosed the usual softened area, and the Fusarium sp. was 
isolated (by the tissue-fragment method) from all except one car- 
nation plant. All the controls remained healthy. 
_ While these experiments were in progress a series of cross- 
- Inoculations was undertaken. Sets of six tins each of plants of 
carnations, Nigella and Delphinium, were inoculated in the twé 
ways already mentioned, each set of three with material from 
cultures from all three host-plants. In this way carnations were 
inoculated with the fungus from carnation, Nigella and Delphi- 
nium; Nigella plants were inoculated with the fungus from 
Nigella, Delphinium and carnation; and Delphinium with the 
fungus from Delphinium, carnation and V igella. The plants in 
all the tins were slightly thinned out, a clear line was made across 
the middle of each tin, and the plants of one-half were set aside as 
controls. At the same time, six lots of Cosmos plants were treated 
similarly and inoculated with the Fusarium from carnation, 
Nigella and Delphinium. — : 
The results of these cross-inoculation experiments were remark- 
ably consistent. All the sets of ‘inoculated plants, including 
those of Cosmos, contracted the wilt disease and succumbed to it; 
the time elapsing between the observation of first signs of sickness 
was of “ Nigella or Delphinium type rather than the carnation 
type, vice-versa. Hor example, certain plants of Nigella 
inoculated with the carnation strain gave, on recovery of the 
fiingus, the distinct carnation 
phere this point from being followed up, as it 
the question of combating the Fusarium with soil 
