GREENHOUSE AND LABORATORY 



43 



stitute is offered by a large, ventilated dark box, black inside, 

 but white outside. The accompanying figure 5 shows in detail 

 such a box (large enough to admit a person who could make 

 sure of its tightness to light), which I used with entire success 

 before I had a dark room at command. 



Passing next to the laboratory, which should directly adjoin 

 the greenhouse, we find its construction much simpler. The 



FIG. 7. CROSS- SECTION THROUGH PHYSIOLOGICAL LABORATORY; 



The various features are explained by Fig. 6 and the text. 



one I have had built, and which has proven perfectly efficient, 

 is shown by figures 6 and 7 and by Plates III and IV. It is 

 built of brick and heated by pipes similar to those of the green- 

 house, though fewer in number and arranged only under the 

 windows. The students' work-tables are of the very simplest 

 pattern. Of the greatest convenience are the central tall tables 

 used for drawing, for the assembling of apparatus, etc. They 



