SCIENTIFIC COMMITTEE, NOVEMBER 8. clxxix 
every tuber. Freshly-cut sections showed a mycelium inside 
the tubers, both in discoloured and normally coloured parts. 
The first result of cultivation was an abundant crop of a Mucor 
(white mould), which soon passed into the zygospore resting 
stage. An abundant crop of bodies of a fungus nature were 
also present about this time in active growth. Later several 
other fungi appeared. The rotten parts showed the presence of 
bacteria, white mites, and nematode worms. Phytophthora was 
not met with in course of the examination. 
The “ scab ” disease has been ascribed to (1) various fungi; 
(2) bacteria; (8) nematode worms ; (4) mites ; (5) an organism 
of a slime-fungus nature (Pseudocommis). The material 
examined was not suited to discriminate the actual cause of 
the disease, because four of the above agencies were present in 
company. The presence of a fungus mycelium in freshly 
exposed sections inclines me to give the precedence to some 
fungus. In the cases examined, moss-litter from a stable was 
used largely in one case; the other had also been manured with 
moss-litter manure, but the source and quantity are not stated. 
This would seem to indicate that such manure offered good 
nourishment to the fungus. Comparing my results with other 
cases recorded, I am inclined to think that the fungus (another 
cause) came from the soil. 
Investigations on Potato-scab have been often made in the 
United States, Belgium, Germany, and France. No definite 
cause has as yet been fixed on, but experiments in preventive 
treatment have been fairly successful. Of the latter the 
following have been tried in the United States and in Europe :— 
1. Corrosive sublimate—the favourite substance used in the 
United States. When seed-tubers are treated before planting 
out with one part of the sublimate in 1,000 of water for one 
to two hours, good results generally follow, although some 
experiments on badly infested land were negative. 
2. Sulphur—also a favourite American remedy. The seed- 
tubers are thoroughly dusted with flowers-of-sulphur before 
planting. One authority speaks highly of good results from 
300 lb. of sulphur per acre applied in the open row, like artificial 
manures, from a drill distributor. The same writer is also 
in favour of a mixture of sulphur and kainit at the rate of 
800 lb. per acre. 
