814 Sterilisation of Soil for Glasshouse Work, [jan., 



partial sterilisation has caused a considerable increase in 

 yield of fruit. 



Vines. — We have not ourselves made any experiments on 

 vines, but from results communicated to us it appears that 

 partial sterilisation has produced marked increases in growth. 

 The method adopted was to inject toluol into the borders. 



Flowers. — Simultaneously with the spinach and radish 

 experiments a number of flowering plants — Clarkias, Ver- 

 benas, Nicotianas, Dianthus — were tried, and all gave better 

 growth and more flowers on the steamed than on the un- 

 treated soil. 



Partial Sterilisation and Food Supply: (b) Plants 

 regularly and sufficiently manured. — If the plant is to be 

 supplied with regular and sufficient doses of manure no ad- 

 vantage is likely to be seen from the food derived from the soil 

 by bacterial action, for no plant can utilise more than a certain 

 amount of food. In such cases partial sterilisation is advan- 

 tageous only for its secondary effects, which may not always 

 be worth having at the cost. Examples are furnished by 

 some of the plants grown in Mr. Tate's glasshouses. The 

 compost was made up freshly with virgin loam and other 

 clean materials, everything being free from disease organisms 

 and pests, as the subsequent growth proved ; the plants were 

 also liberally manured. 



Cinerarias certainly started somewhat better in the steamed 

 compost, and began coming into flower before those on the 

 untreated soil, but their weekly dose of cow manure water 

 clearly sufficed for their needs, the limiting factor now being 

 not food but something else. Consequently when the plants 

 were moved into the conservatory there was little if anything 

 to choose between them, and nothing to justify the trouble 

 of partial sterilisation. 



Carnations and Malmaisons fed regularly with a pro- 

 prietary carnation manure made full growth on the untreated 

 soil, and therefore did no better on the steamed soil. The 

 same thing happened in the case of Schizanthus. 



Melons ripened rather sooner on the steamed soil than on 

 the untreated, and in the case of one variety (Sutton's Ai) 

 gave a more rounded and somewhat smaller fruit. Other- 

 wise the crops on the two soils seemed identical. The experi- 



