CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 47 



contains little or no starch, and its microscoi>ical strnctnre is that of the 

 sclerotic niycelia. The sclerotinni is Uioked upon as a hard compact 

 mass of imperfectly developed mycelia. It api)ears to be about a month 

 from the time the fungus invades the ovary until the ergot is fully 

 formed. 



The ergot is the dormant form of the fungus, and remains in this con- 

 dition until autumn, or usually until the next spring. If at this time it 

 is in contact with the damp ground it germinates and stromata grow 

 from its surface (PI. VIII, Fig. 7). Tliese consist of a long stalk and a 

 globular head, and become perfect fruiting fungi. In the head a large 

 number of flask-shaped perithecia are formed (see PI. VIII, Fig. 8)^ 

 which are filled from the bottom with a number of asci (PI. VIII, Fig. 9), 

 each of which contains several slender filiform spores (PI. VIII, Fig. 10). 



When the spores reach the young flowers of rye, led top or other 

 nearly allied grasses, they germinate and form a mycelium which 

 invades the wall of the ovary and again produces a sphacelia. With 

 this the cycle of development of the fungus is completed and we 

 probably have its entire life history. The meteorological conditions 

 most favorable for the production of ergot are not well known. It has 

 been asserted that it only appears in large quantities in rainy seasons^ 

 but others believe that moisture has little or no influence on its devel- 

 opment. It is also uncertain whether more than one S)>ecies of clavi- 

 ceps is concerned in the production of ergot in the different varieties of 

 grasses. The ergot of the red-top hay in Missouri and Illinois produced 

 identical effects with that in the wild rye of Kansas, and it would 

 therefore appear that the phj'siological effects are substantially the 

 same even though the species growing upon these two plants may be 

 different. 



The grains of ergot of rye are from half an inch to over an inch in 

 length, and from one-fifteenth to one-sixth of an inch in diameter ; they 

 are nearly cylindrical, sometimes slightly ribbed and farrowed, and often 

 have irregular fissures; they are curved, and taper toward the ends. 

 The color of the surface varies from dark violet to blue black or black ; 

 the interior is white, often tinted with violet. The ergot of wild rye, 

 blite grass, and red top has the same general appearance, but the 

 grains are sujaller. In red top many of the grains are so small that 

 they are only recognized with dilficulty by the unaided eye. Some- 

 times the taste is pronounced and disagreeable; but the ergot in the 

 wild rye of Kansas, where the outbreaks ot disease occurred, was'al- 

 most or entirely without taste, and certainly was in no sense disagreea- 

 ble when masticated. 



Chemical vomposiUon. — Ergot is a very com))lt'x material when con- 

 sidered chemically, and although it has been studied by many com[)e- 

 tent chemists, there is yet much doubt as to the nature of a number of 

 the substances which have been found in it. About 35 per cent, of its 

 weight consists of a thick, fluid, (IxcmI oil, which is now believed to be 



