32 



PROTEIN POISONS 



able and free from contamination. This tank, photographs 

 of which are here given, was first put into operation in 1900, 

 and was described in the following year 1 (Figs. 1, 2, 3, 4). 

 A copper tank ten feet long, two feet wide, and four 



FIG. 4 



The incubating room, lids raised. 



inches deep, with a trough around the edge one inch deep, 

 has a cover which, when lowered into place, rests in the 

 trough. This tank is supported by an iron frame of gas 

 piping, the legs of which rest on rollers, so that the whole 



] Trans. Assoc. Amer. Phys., 1901, xvi, 217. 



