Nature, XXX

220. ergon (er'gon), n. [ ergot1 (ergot), n. [F. ergot , also argot , a spur, the extremity of a dead branch, in bot. ergot; origin unknown.] 1. In farriery , a stub, like a piece of soft horn, of about the size of a chestnut, situated behind and below the pastern-joint, and commonly hidden under the tuft of the fetlock.-2. A morbid growth arising from a diseased condition of the ovary of various gra es, caused by a fungus of the genus Claviceps. The growth of the fungus begins by the formation of a filamentous mycelium upon the surface of the ovary, which it destroys and displaces, retaining approximately its shape. The surface of this ti ue is marked by furrows. At this stage conidia are produced upon the tips of short hyp he; and in this form it was melder hard i i species generic name Sphacelia (which has become a common name coordinate with sclerotium). When the formation of conidia is at its height, a thick belt of more compact hyphæ is formed at the base of the ma . This a umes a dark-violet color, and continues to grow, pushing upward the sphacelia, which is torn from its attachments, and soon falls off. IMG:content-0676.png:[merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small] 1. Cro -section of the ovary (sphacelia), in the early stage of the fungus, showing the mycelium ( a a a ), conidiophores (db), and conidia (cc). 2. Ergot on its supporting gra . 3. Fully developed ergot (a), bearing the furrowed remains of the ovary (6). 4. Ergot which has produced 7 stromata. 5. Longitudinal medial section of a stroma, showing the numerous perithecia Just beneath the surface. 6. Longitudinal medial section of a perithecium, showing the slender asci arising from the base. 7. An isolated ascus from which the filiform spores are escaping. (Figs. 2, 3, and 4 somewhat reduced; 5, magnífied; 1, 6, and 7, highly magnified.) The resulting structure is the sclerotium or ergot . It is a horn-like ma , often one inch in length. It lies dormant till fall or usually till the following spring, when branches arise in a tuft. Each becomes a stroma, consisting of a stalk and a small head. In the head are formed a num ber of flask-shaped perithecia, each containing many asci, of which each in turn incloses several filiform spores. The ergot of rye is caused by Claviceps purpure a . Ergot is said to cause a sort of gangrene in cattle, especially in the feet. It is used in medicine to cause contraction of the uterus and of the arterioles and as an abortifacient, and also in certain morbid states of the cerebrospinal axis, where its effect may or may not be due entirely to its action on the ve els. Also called spurred rye. 3. In an at ., the calcar, spur, or hippocampus minor of the brain. [Rare.] ergot2+ (er'got), v. [Also erg at ; ergoter (= Sp. ergotear ), cavil, quibble, ergo , trans . To infer; arrive at. Little doth it concern us what the schoolmen erg at in their schools.