We have already referred to the fact that some kinds of distilled water become perfectly gelatinous on keeping. The same thing takes place with some kinds of mixtures. The following are cases which have been observed by correspondents of The Chemist and Druggist:

Two days after this mixture was dispensed it was returned a perfectly gelatinous mass. It had every appearance of a perfect mixture when sent out, and remained so for about twelve hours, when it changed in colour from almost transparent brown to opaque pink, and became thick and ropy. A mixture containing syr. pap. alb. and syr. scillae became ropy and of a pink colour when made with old syr. papav., but when made with fresh syrup it kept all right.

Such changes are by no means uncommon, and cannot as a rule be forecast. They are due to one of two micro-organisms -Bacillus viscosus saccharic Kramer, which acts in neutral or slightly alkaline solutions containing sucrose, albuminoids, and mineral salts, or B. viscosus vini, Kramer, which grows in acid solutions containing glucose, albuminoids, and mineral salts. In the process of growth the bacilli set up fermentation and produce a viscous substance, C6H10O5, which has all the characters of metamorphosed cellulose, and is precipitated by alcohol. The fermentation takes place in mixtures containing less than 20 per cent of alcohol. It is precisely the same thing that occurs in ropy ginger-beer. The bacilli doubtless exist in one or other of the galenical preparations, and only require the needful conditions of growth for development. Ergot preparations are especially prone to set up the fermentation.