Xxil PROCEEDINGS. 



It is well known that the exhalations from the bodies of animals 

 have a poisonous effect if breathed, even tho much diluted with air. 

 The classic researches of Pettenkofer. Brown-Sequard, d'Arsonval, 

 Lehman, Merkel, Parkes, and others, have proved the presence of an 

 organic poison in air which has been breathed by man or other animals. 

 Its exact constitution is not known, but the effects of " Pettenkofer's 

 man-poison " are apparent in every school-room. They are, headache, 

 drowsiness, slight fever, and a general retardation of all reactions to 

 stimuli. Partial loss of the power of inhibition is also noticeable. Less 

 apparent, but more important, are the general weakening of vitality and 

 the greater susceptibility to disease which follow prolonged breathing of 

 impure air. 



These effects are more easily seen in the weak and anaemic than in 

 vigorous persons. It was the observation of the less vigorous students 

 at Truro which first led me to suspect that the air in the Normal School 

 might be one cause, at least, of the decrease in power which I had 

 noticed. We have, as do all schools, pupils who, when at their best, are 

 just able to keep np with the class, who are, mentally or physically, 

 near the fatigue-point. A slight interference with their normal activity 

 throws them off their balance, and they must drop behind. Not infre- 

 quently pupils come to us enfeebled by excessive study in preparation 

 for examinations. Under favorable conditions they might do well, but 

 if subjected to further strain they may break down. With these two 

 classes of students, poisoning by impure air may make the difference 

 between success and failure. At all times, and with all classes, it causes 

 a determinate decrease in the amount of work, mental or physical, 

 which is done with a given expenditure of energy. Especially where 

 the system of public education is most highly developed and most 

 strenuously applied, the evil effects of this poison have been most 

 apparent. 



In testing the air in the Normal School, the method and apparatus 

 of Prof. Hch. Wolpert of Nuremburg was adopted. The chemical basis 

 of this method is the fact that an alkaline solution of sodium carbonate 

 becomes neutral by the absorption of carbon dioxid. If the alkaline 

 solution be colored red by phenol phthalein, when the solution becomes 

 neutral the color disappears. Thus, with a given amount of sodium 

 carbonate, the decolorization of the liquid shows that a certain amount 

 of carbon dioxid has been absorbed. If this carbon dioxid come from a 



