life-history and relations of the fungi under consideration. The 

 results of this study have shed much new light upon the subject, 

 showing especially the existence and common occurrence of a very 

 destructive disease which we designate here as the " Drop," hitherto 

 entirely unrecognized in lettuce. This disease has previously been 

 confused with another much less important one which is similar to 

 it in many ways, but differs radically in several very important 

 respects. This is the trouble caused by the attacks of Botrytis. 

 We have shown that the more destructive disease is caused by a 

 fungus entirely distinct from that to which the disease has been 

 generally ascribed and the life-history of which in the greenhouse 

 we have been able to trace out very completely. Another disease 

 of lettuce has also been found which has not previously been 

 described. This is caused by a species of Rhizoctonia, the devel- 

 opment of which has been found to be similar to that of the Drop in 

 many respects. Peculiarities have been found in the development 

 and growth of these fungi which make their control possible and 

 methods have been developed by which this result can be practically 

 and economically attained. 



Lettuce Growing in Massachusetts. 



It is probable that very few people outside of the district have 

 any idea of the extent to which lettuce is grown in greenhouses in 

 the vicinity of Boston. Located particularly in the towns of Arling- 

 ton and Belmont, this industry has seen in the past few years an 

 almost phenomenal development. Individual growers estimate the 

 space in their establishments covered by modern forcing houses in 

 acres, and single houses with a length of five and even six hundred 

 feet or more are to be seen. Greenhouse lettuce is also grown in 

 other parts of the Commonwealth and the industry is increasing 

 near all the larger cities and towns, but no other portion of the 

 State and very few in the entire country can compare with the 

 Boston district, where a large part of the lettuce for the markets of 

 New England, as well as New York city and beyond, is grown. No 

 better example can be found of a highly specialized agricultural 

 industry. From the time when the first crop is matured in early 

 winter until (according to the general practice) cucumbers or toma- 

 toes are put into the houses in the spring, lettuce is turned out very 



