240 Transactions British Mycological Society. 
in a pure culture grown on bean pods, obtained spores of the 
same size as those produced on apple branches. Measurements 
were made of 1000 conidia from a pure culture grown on malt 
agar. Here the length varied from 17-5 u to 295 u, the majority 
being 25 in length, and the width varied from 6 to 10-5 p, the 
majority being 7-5 in width. 
The graphs on p. 239 give the frequency curves for conidia 
produced naturally and artificially. 
5. Germination of conidia. 
The conidia germinate very readily even in distilled water, 
and the germination of single spores was followed in a number 
of cases. In Pl. X, fig. 12 (a) represents a conidium from a 
hanging drop culture in a dilute solution of malt extract. It 
remained on a bench in the laboratory at about a temperature 
of 15° C. during the daytime and slightly less at night. In 16 
hours a germ tube had been put out from one side, nearer the 
round end than the pointed end of the spore. When the culture 
was 48 hours old, this germ tube had grown considerably, be- 
coming septate and branched, while a cross wall had formed in 
the spore dividing it into two cells approximately equal in size. 
When four days old, the spore was found to have put out a 
second germ tube which arose from the other end of the spore, 
that is, the pointed end. Each of these germ tubes grew and 
branched giving rise to the colony shown in Pl.eX, fig. 12 (h). 
Observations of other germinating spores showed that the pro- 
cedure described above approximates the normal. The first germ 
tube may arise from either end of the spore and is usually 
initiated before the spore divides into two cells. The second 
germ tube is developed from the second cell and therefore from 
the opposite end of the spore within about three days. 
INOCULATIONS. 
The association of Myxosporium corticolum Edgert. with the 
bark canker disease has been recorded by four sets of observers 
previously and it seems extremely probable that it is respon- 
sible for the disease. Lewis(z) only, however, has obtained a 
successful infection from an artificial inoculation. “‘On one 
branch inoculated with Myxosporium the typical killing back 
which is characteristic of branches on which this fungus so 
frequently occurs was found. Other branches failed to show 
any injury whatever due to the inoculations.’’ The exact number 
of inoculations was not recorded but seventeen are definitely 
mentioned. 
The total number of inoculations made at Long Ashton 
amount to 45, but so far no definite signs of successful infection 
