1898.] PUBLIC DOCUMENT — No. 33. 47 



KEPOET OF THE BOTAOTSTS. 



GEORGE E. STONE, RALPH E. SMITH. 



Our work during the past year has been in general a con- 

 tinuation of that of the year preceding. In this, as in other 

 departments of the station, the work falls under two classes : 

 first, examination of material sent in for determination and 

 answering of inquiries ; second, investigations of problems 

 connected with plant physiology and pathology. 



For the purpose of investigation the greenhouse has been 

 remodelled and enlarged during the past summer, so as to 

 admit of carrying on experiments under more desirable con- 

 ditions. It is quite essential, in experimenting with plants, 

 that the numl)er employed should be large enough to make 

 it possible to draw deductions from the results with a rea- 

 sonable degree of certainty that errors arising from indi- 

 vidual variation have been counterbalanced. It is also 

 essential that the heat, light and moisture conditions should 

 be equal upon each series of plants under consideration, and 

 that these conditions should compare as closely as possible 

 with the best method of cultivation. In the construction of 

 the experiment house these details have been considered as 

 carefully as possible. The house as now arranged consists 

 of several sections, in which different temperature's can be 

 maintained, for growing tomatoes, cucumbers, lettuce and 

 other important plants sul)ject to destructive diseases. The 

 amount of money invested in the production of greenhouse 

 crops is large and continually increasing, and no small part 

 of our work consists in the study of the various diseases 

 which affect them. 



For the last three years we have been investigating meth- 

 ods of controlling the gall-forming nematode worm, which 

 affects cucumbers, tomatoes, English violets, roses, cyclam- 



