148 GENERAL PHYSIOLOGY 



much as is ordinarily believed. In order to disinfect a room 

 having a thousand cubic feet of air space (10 by 10 by 10 ft.), 

 it is necessary that from three to five pounds of sulphur be 

 burned in it. Furthermore, since burning or oxidizing of 

 sulphur forms sulphur dioxide, and sulphur dioxide is not a 

 good disinfectant, it is not enough merely to burn sulphur. 

 There must be moisture present. Moisture can be obtained 

 by means of steam. The active disinfecting agent formed by 

 the union of the sulphur dioxide and the water is sulphurous 

 acid. Sulphurous acid is a good disinfectant but it is also an 

 ideal bleaching agent, and when it is used all of the draperies 

 in a room are destroyed. Unless this occurs, the disinfecting 

 process has not been properly carried out, and if it is done, of 

 course the draperies, wall paper, or whatever it may be, are 

 rendered useless. A good deal of misunderstanding, then, 

 has prevailed in the use of sulphur, and it is not popular at 

 the present time for family use. There are conditions, how- 

 ever, under which it works well, and for certain purposes it has 

 no competitor. This is true where it is desirable to kill higher 

 forms of life, such as insects and rodents, and it has very 

 great value for certain lines of work, such as in the disinfection 

 of the holds of infected ships where it is desired to kill rats, 

 mice, and insects. 



Formaldehyde is a chemical substance which has come into 

 use as a disinfectant within recent years and has become 

 deservedly popular. It is a gas formed by the incomplete 

 oxidation of methyl alcohol. Although a gas, it is put upon 



