Hoyt: CULTURES OF SPIROGYRA 357 
TABLE IV 
EFFECT OF VARIOUS OF TAP AND DISTILLED WATER UPON THEIR TOXICITY 
Tap Ordina 
Treatment Water Distilled Water 
Distilled in glass (distillate)........ so cent 
Distilled in glass (undistilled residue).............-+++ + on 
Distilled with carbon (distillate). ... mip =a 
Distilled with carbon (undistilled residue)...........-- + = 
Pleated t6:r44 "Coe ee ac ee ee o +* 
* Still toxic, but much improved. 
