most 130 days. pass annually from one pupil to another, without any virulent germs (tuberculosis, diphtheria, coli bacillus, Various methods of disinfecting books have been in- attempt being made to prevent the propagation of etc.) placed on the edges, or even in the center of the vented. The most… … caused to rise and fall, alternately, was entirely free from scarlet Fig. 4.—Agitating the felt saturated with formic aldehyde. by cams placed on a cylinder which fever, received a letter from the is turned by a crank. A ventilating fan and a sliding child's governess, who was then traveling in…
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