10 
W. J. Dowson, 
persed in a small drop of sterile water upon a sterile glass slide. This 
process of gently touching the cultures with the point of the needle, and 
transferring to the water drop was repeated 3 or 4 times. The drop was 
then examined under the low power of the microscope to make sure 
that the spores were present in sufficient quantity to ensure that one dip 
of a very small platinium loop into the drop would bring away 3 or 
4 spores. Sometimes no spores were picked up at all, sometimes 
only one, and occasionally as many as 9. On an average, however, 
3 or 4 spores were delivered 
by each touch of the charged 
platinium loop on to the agar 
drop. Each drop was inoculated 
at the edge in four different 
places, corresponding to the 
cardinal points of the compass. 
In this way it was easy to 
distinguish the spores again 
when observing under the 
microscope. Care was taken 
that 'the agar surface was as 
little scratched and indented 
as possible in the process of 
inoculation as the refraction 
and shadows caused by these 
seriously interfered with the 
accurate observation of the 
germinating spores. Those 
spores were observed which 
lay upon an even surface which 
was practically parallel to the 
glass slide. By having thor¬ 
oughly clean glass cover-slips 
which acted as the top of the 
hanging-drop slide, it was found 
possible to obtain drops of fairly 
large area in proportion to 
their thickness, the central 
portion of the drop being a 
flat plane only slightly if at all 
convex. This was only possible 
when solid media were used. With liquid media, such as normal Pasteur 
solution, the drops gave convex surfaces, so that the spores very seldom 
lay in a plane parallel to the bottom of the glass slide. Three slides 
of each medium were made. 
The germination upon all the solid media, and upon normal Pasteur- 
solution was the same. After 3—4 hours a germ hyplia was pushed out 
at one end of the spore, a little to one side of the long axis of the spore 
(fig. I ). Sometimes two germ hypliae were formed, one at one end, and 
the other at the opposite end of the spore (see fig. 1 b). The spores 
increased a little in size, more in breadth than in length. The germinating 
spores measured 20 ju —30^ x 10 u — 13 ju. The first germ hyphae in- 
Figs. 1 —10: Heterosporium Betae (x 215). 
Figs. 1 and3: Spores germinating on salep agar. 
— 2: Spore germinating in water. —4 and 5: Young 
myeelia. — 6 and 7: Hyphae growing into 
the air studied with water drops. — 8: Short 
coloured hyphae growing downwards into sub¬ 
stratum. — 9: Young conidiophores, showing 
two chains of two spores each and the beginning 
of the prolongation of the conidia-bearing hyphae. 
The aerial portions are covered with water drops. 
— 10: Co nidi a. 
