Mildew in Books

In answer to B. I mention that the following facts connected with mildew in books have been elicited. The mildew referred to is that which shows itself in the form of roundish or irregular brown spots. It is usually most abundant in those parts which are most exposed to the air. In making a microscopic examination of the spots, I ascertained that there was no new structure present; but in manipulating I found that these spots absorbed water more rapidly than the rest of the paper. On applying litmus, these spots were found to have a powerful acid reaction. On submitting the matter to a chemica…