112 THE CANADIAN ENTOMOLOGIST. 



In a later communication Dr. Bail states that the use of mould has 

 been the secret in brewing formerly certain kinds of a strong and well- 

 reputed beer. 



For the so-called jopenbier in Danzig the mash was not used before 

 the forests of mould grown on its surface had sunk to the bottom — or, in 

 other words, till the spores of the mould were sown by themselves on 

 the mash. 



Dr. Bail has proved by numerous experiments that healthy insects 

 brought in contact with mash and fed with it are directly infested by the 

 spores of the fungus with fatal consequence. These facts, not belonging 

 strictly to the main part of his experiments, were observed first by 

 chance and later on purpose. The most different insects, Mies, mosquitoes, 

 caterpillars, showed all the same results. The experiments were made in 

 such a delicate manner that a small drop of blood taken with an oculist's 

 needle from the abdomen of a house-fly left the animal so far intact that 

 the same operation could be repeated in two days again. Both drops 

 examined with the microscope proved to be filled with spores of fungus. 



More to the point are epizootics produced by this fungus and observed 

 on insects in the open air. 



A really pestilential epizootic of the common dung-fly was observed 

 in 1867. Not only those, but many other insects, died in the same locality 

 and in the same manner ; also other species of flies and gnats, the cater- 

 pillars of moths and of Phalaenids, and the common hairy caterpillars of a 

 moth which is very nearly related to the famous hairy caterpillar of the 

 Boston Common. Of some species the destruction was so complete that 

 the next year they were very rare. During those years the caterpillars of 

 two species of moths had destroyed pine forests belonging to the State 

 and valued at several millions, and a larger calamity was imminent, when 

 suddenly all caterpillars died from the same fungus. 



Similar observations have been made in other places in Europe and 

 here. Mr. Trouvelot formerly began in Medford, Mass., the raising of the 

 Polyphemus moth for silk, and was successful enough to get a prize in 

 the Paris Exhibition of 1867. Unfortunately he brought home from Paris 

 eggs of another species from China, and purported to be superior for 

 silk-raising in the open air. Those eggs proved to be infested by fungus, 

 and the caterpillars hatched from them died, but not those alone. All 

 caterpillars of the Polyphemus moth became infested, and even most of 

 the other indigenous species living on the twelve acres of shrub land 



