46 DIPLODIA CORCHORI SYD. 
examination a week later showed that Diplodia hyphe had travelled through the 
cortex and reached the wood 3 cortex and phloem were practically destroyed all 
round the stem for a stretch of several inches. The other plant remained green 
and healthy in its upper part, despite the fact that it also was completely rmged by 
the fungus at the seat of infection. An examination of the diseased section of 
the stem showed that the plant had reacted against the parasite and had formed 
new vascular tissue to one side of, and external to, the old tissue. 
Experiment VII. Two plants, sown in a pot on 12th March, 1918, were 
infected from a young agar culture of D. Corchori on 3rd June, 1918. One plant 
was infected on the stem surface and the other at the base of an axillary shoot ; 
both infections were jacketed with lamp chimneys. A brown stain appeared at 
the seat of infection in 24 hours, and on 7th June had spread up and down and 
round the stems with the production of pyenidia. One plant died a few days later 
but the second survived with the formation of fresh vascular tissue as in the last 
experiment. Controls remained healthy. 
Experiment VIIT. Three plants, sown ina pot on 12th March, 1918, were 
infected from a young agar culture of D. Corchori on 7th June, 1918 ; all the infec- 
tions were carried out on the uninjured stem surface and were jacketed with lamp 
chimneys. After 24 hours all infections had taken and a brown stain was spread- 
ing over about $ inch of the stem at the seat of infection. Two of the infections 
were removed for microscopic work and the third was left standing, its glass jacket 
being removed on 10th June, 1918. This plant died with typical symptoms of 
Diplodia disease during the next week. A characteristic of the diseased stems 
in all inoculations, and one which has also been observed in the field, is the longi- 
tudinal splitting of the diseased bark by which the surface-of the wood is laid 
bare. In some cases there appears to be an actual separation of the constituents 
of the bast fibre, and it may be inferred that the fungus has an action upon the 
tissues which is possibly analogous to that which takes place during retting. 
Controls remained healthy. 
Experiment IX. Two plants, sown in a pot, on 12th March, 1918, were 
infected on 8th June, 1918, from a young culture of D. Corchori. These infections 
were made at 7 p.m, and were jacketed with lamp chimneys in the usual way. At 
7 a.m. on 9th June, 1918, after 12 hows, the infections had taken and a small 
b-own stain was spreading on the stem surface. Both these stems were removed, 
and the tissues fixed in chrome-acetic, for microscopic examination. 
Experiment X. Four plants in pot culture, sown on 12th March, 1918, were 
infected on 25th July, 1918. These plants were about 6 feet high and 1 inch 
thick at the base of the stem ; the infections were jacketed with lamp chimney. 
None of the infections took. Small brown stains at the point of infection occurred 
