742 



dead tissue of which parasites certainly are not the cause. Black fungi 

 may later infest these spots and then this complication is described as the 

 " H ormondendron" disease. The spotted necrosis is, however, not a disease 

 peculiar to regions of flying ashes but it undoubtedly occurs most inten- 

 sively there. I found it could be lessened by a heavy application of lime. 



The opinions handed down by Steffeck^ give the best references to the 

 injurious action of hydrogen sulfid. In them the repeated decrease in the 

 value of the harvest by a mechanical coating of the soil is also considered. 

 I also know of cases in which a deposition of ashes on vegetable plants, 

 especially varieties of cabbage, was so heavy and could be removed to such 

 a slight extent that the quality of the plants became poor, or they were abso- 

 lutely unsalable. If fodder carrots and sugar beets had been heavily covered 

 and their leaf heads used later as fodder some of the animals died. Incred- 

 ibly large amounts of ashes were found in the stomachs of these animals. 



Hydrogen Sulfid. 



In consideration of our theory that hydrogen sulfid may be formed in 

 certain heavy kinds of soil after flying ashes have been deposited on them, 

 I made some experiments with barley. In some pots, pieces of potassium 

 (poly sulfids) from sulphur liver were laid between the young barley plants ; 

 in other they were put in the water in saucers in which the pots of barley 

 stood. A piece of lead paper, laid between the plants, slowly turned brown. 

 After six days the leaves began to turn yellow usually, in fact, beginning at 

 the center, more rarely at the tip. The discolored areas appeared to be 

 more watery and transparent than when the yellow discoloration was pro- 

 duced by other causes-. A wilting of the tissue followed the yellow discol- 

 oration and a drying of the green leaf surface lying above it, together with 

 the assumption of a grayish yellow color. 



The first symptom of the disease is always the bleaching of the chloro- 

 phyll coloring matter, which at once begins to spread into the cytoplasm. 

 This is not preceded, nor accompanied, as in other cases of poisoning, by a 

 contraction of the primordial pouch (or a shrivelling of the chloroplasts). 

 Instead of this, in places, the passing over of the cell water into- the inter- 

 cellular spaces becomes noticeable, thereby explaining the transparent 

 appearance of the yellowish areas. The outlines of the individual chloro- 

 plasts then disappear up to the appearance of a granular mass which is 

 contracted in the centre of the whole cloudy, pale yellowish, green cypto- 

 plasm. The impression given is that here the cell contents as a whole swell 

 up into an uniform, doughy mass, while in the action of the hydrochlorin 

 and hydrochloric acid shrivelling phenomena are perceived and, with sul- 

 furous acid,. a process of drying of the contents which remain differentiated. 



1 Steffeck, Die durch g-ewerbliche Einwirkung-en hervorg-erufenen Flurschaden 

 iind Verunieinigung-en von Wasserlaufen und Teichen. Magdeburg-er Zeitung 1907. 

 Nos. 329 and 331. 



2 Sorauer, P. Beitrag' zur anatomischen Analyse rauchbeschadigter Pflanzen. 

 Landwirtsch. Jahrb. 1904, p. 643. 



