Again, if the stocks be supplied in the late autumn with syrup too watery for the bees to seal over in the cells, contact with air sets up a chemical change, and a certain amount of acid is generated, which makes the honey most prejudicial to the health of the stock, by deranging their digestive functions. Thirdly, if during the winter time, when the insects are closely confined to their dwellings by the weather, and when they are, under ordinary conditions, very quiescent, they be disturbed and excited, they are apt to gorge themselves with food; and having no natural means of working off the extra quantity they have taken, the system is overloaded, and the stomach and intestines suffer from the too great burden thrown on them. The occurrence of this malady is indicated by the altered appearance and odour of the excrement, which, instead of being reddish yellow, becomes of a muddy black colour, and has an intolerably foul smell. It is, moreover, deposited by the weakened insects, contrary to their cleanly habits, on the combs, the inner walls of the hives, on the floor-board, and at the entrance of their dwellings. The avoidance of the causes of the generation of the disease is a comparatively easy matter. The means of cure are, first, the removal of the reasons for its occurrence, and, secondly, the immediate and thorough cleansing of all parts of a hive soiled by the sick bees. It is still better, if possible, to remove the stock into a perfectly fresh dwelling; and it is advisable to take away all combs with unsealed honey, and substitute sealed stores, or to feed the bees with barley-sugar. "Foul-brood" is a much more formidable malady, and is often encountered. It is, indeed, a terror to apiarians, for not only is it very fatal to any stock in which it appears, but, from its ready contagiousness, it may depopulate any number of previously healthy communities, and may extend from one apiary to several others in the neighbourhood. As the name implies, it has been thought to be a disease of the larvæ, and there are said to be two kinds, called respectively the _dry_ and the _wet_. The former of these is much less serious, and is not contagious. The young merely die in their cells; their bodies desiccate, and there is an end of the matter. In the other variety, the brood remains dark and shiny in the hatching-places, and emits a most offensive odour, perceptible at some distance from the hive. When the mischief is very great, combs are sometimes removed which are masses of corruption and fœtor.