A specimen of Gyromitra esculenta was forwarded to me from Portland, Maine, by a member of a mycological club of that city, who stated that this mushroom was quite abundant in the early spring in the woods near Portland and that the plants were eaten by the members of the club, _care being taken to use them only when perfectly fresh_. Indigestion and nausea followed the eating of old specimens, but the general opinion was "favorable to the Gyromitra as an addition to the table." (See page 6, part 2, of this series.) Prof. Chas. H. Peck, of Albany, while placing this mushroom in his edible list as one which he had repeatedly tested, advises that it should be eaten only when perfectly fresh, as nausea and sickness had been known to result from the eating of specimens which had been kept twenty-four hours before cooking. I forwarded a number of drawings of the American species of G. _esculenta_, together with a dried specimen of the same received from Maine, to Prof. Kobert, who identified both drawings and specimen as the _Gyromitra esculenta_ of Fries, synonymous with the _Helvella esculenta_ of Persoon. Prof. Kobert also informs me that he finds the fresh G. _esculenta_ perfectly harmless when freed of the water of the first boiling. He says: "My wife and I eat it very often, when in fresh condition, and after the first water in which it is boiled is poured off." The active poisonous principle of this mushroom is the _helvellic acid_, which is soluble in hot water. When the mushroom is gathered fresh and _quickly dried_ it is then also innoxious. In this respect it differs from the species _A. muscaria_, in which the poisonous alkaloid _muscarin_ is not destroyed in the drying, but remains unchanged for years in the dried mushroom. The fact that there have been seemingly well-authenticated cases of fatal poisoning in the eating of this mushroom shows that if used at all it should be eaten _only when the conditions essential to safety are most carefully observed_, and as these mushrooms show varying qualities, according to local conditions of soil and climate, etc., amateurs finding it in localities where it has not been heretofore used should proceed tentatively and with much care before venturing to eat it freely. POISONOUS AND DELETERIOUS MUSHROOMS OF THE LACTAR, RUSSULA, AND BOLETUS GROUPS. Lactarius _torminosus_ Fries contains in its milky juice an acrid resin which causes inflammation of the stomach and of the alimentary canal. When parboiled and the first water removed, it has been eaten without injurious effects. Lactarius _plumbeus_ Bull., Lactarius _uvidus_ Fries, Lactarius _turpis_ Weinn., and Lactarius _pyrogalus_ Bull., all acrid mushrooms, according to Kobert, are similarly poisonous. Of the "Erdschieber" (Lactarius _vellereus_) and the "Pfefferling" (Lactarius piperatus Scop.) Kobert says they are eaten in parts of Russia and in some places in Germany, but that neither is very safe.