518 



SCIENCE 



[N. S. Vol. LI. No. 1325 



5. This fungus when inoculated in pure cul- 

 ture, either as spores, mycelium or infected 

 wheat tissue, on the unwounded lower inter- 

 nodes of -wheat seedlings in moist chambers 

 produced a condition of disease indistinguish- 

 able from foot-rot as it occurred in the field. 



6. Plants thus inoculated when placed in a 

 moist chamber soon bore numerous spores of 

 the fungus. 



7. Wheat planted in soil in pots or benches 

 ■with an inoculum consisting of this fungus, 

 either as spores or as a pure culture on wheat, 

 developed typical foot-rot. 



8. Wheat when planted in infested soil in 

 the greenhouse developed typical foot-rot and 

 when placed in a moist chamber bore the same 

 fungus found so constantly in association with 

 the disease in the field. 



9. The fungus in question is a typical Eel- 

 Tninthosporium as the genus is now under- 

 stood. It grows luxuriantly on wheat agar, 

 com meal agar and numerous other media and 

 on autoclaved leaves or stems of various ce- 

 reals. The spores, observed as grown on 

 autoclaved wheat leaves or stems in humid air, 

 are from 24 to 122 M long, the majority of them 

 falling within the limits 80-90 f with septa or 

 pseudo-septa varying from to 13, usually 

 about 5-10. The spores are typically thickest 

 in the region about midway between the base 

 and the middle point of the spore, approaching 

 a narrow or broadly elliptical shape, tapering 

 somewhat toward each end. They possess an 

 outer dark wall that is thin and extremely 

 fragile and an inner, colorless, thick wall that 

 is frequently soft, gelatinous. Both of these 

 characters of spore wall seem to be common in 

 several other species of Helmintliosporium. 

 The spores usually, perhaps always, gei-minate 

 either from one or both ends, not laterally, 

 and are functionally one-celled. 



Further discussion of the morphological and 

 histological features and the relation of this 

 Helminihosporium to other species common on 

 cereals will be presented later. 



All of the above refers solely to foot-rot as 

 observed and studied in material originating 

 in Madison Co., Illinois, or cultures derived 

 from such material. 



It is to be noted that this cereal disease, 

 while of the general type of foot-rot known 

 heretofore in Europe, Australia and elsewhere, 

 is caused by an organism not heretofore desig- 

 nated as a cause of foot-rot in any of the pub- 

 lications on foot-rot in such countries. 



The foot-rot found in Illinois, therefore, 

 should be recognized as a disease quite distinct 

 from all others of similar type that have been 

 described previously. It is clear from experi- 

 mental evidence that it is soil^borne and it is 

 probable that it is also seed-'borne. How seri- 

 ous the disease may prove to be, how depend- 

 ent upon environmental conditions of climate 

 and soil, can 'be told only after one or more 

 years of additional observation. 



F. L. Stevens 

 University op Illinois, 



THE AMERICAN ASSOCIATION FOR 

 THE ADVANCEMENT OF SCIENCE 

 SECTION E— GEOLOGY AND GEOGRAPHY 



A Biochemical theory of the origin of Indianaite : 

 W. N. Logan. 



Our decreasing natural gas supply: J. A. 

 BowNOCKER. A study was made of the nat- 

 ural gas supply from the records of four large 

 companies in West Virginia, Pennsylvania and 

 Ohio. It was shown that the open flow of 

 new wells in West Virginia has decreased 79 

 per cent, in 10 years; in northwest Pennsylvania 

 70 per cent, in 7 years, and in southwest Penn- 

 Bylvania 12 per cent, in 10 years. Oanges in rock 

 pressure of new wells are similar. Thus in north- 

 west Pennsylvania there has been a decrease of 37 

 per cent, in 7 years, and in southwest Pennsyl- 

 vania a decrease of 34 per cent, in 10 years. In 

 the northern half of West Virginia there has been 

 a decrease of 38 per cent, in the same period. 

 Naturally there has been a proportional decrease 

 in the rock pressure and open flow of all wells. 

 In Ohio the drilling of new territory has kept the 

 averages at a higher figure, but in spite of this 

 the production of gas in the state is decreasing. 

 Ohio gets 60 per cent, of her supply from West 

 Virginia; Pennsylvania about 33 per cent.; Ken- 

 tucky about 75 per cent., while Maryland and 

 Indiana each draw on the state in a limited way. 

 Manifestly the future supply depends largely on 

 West Virginia. For the two years closing June 30, 



