826 EXPERIMENT STATION RECORD. 



gone. The author states that in order to have the seed germinate, it 

 is necessary that the reserve material shall remain chemically unchanged, 

 that the embryo shall preserve its structure, that an enzym be pres- 

 ent for the reduction of the reserve material and that the embryo 

 shall remain in contact with the reserve material for the proper transfer 

 of the elaborated reserve material. Examination of a large number of 

 specimens failed to show a single instance in which the embryo 

 remained in contact with the reserve material. The embryo main- 

 tained its cellular structure, but had undergone very decided chemical 

 changes. The scutellum and the rest of the embryo had become a 

 reddish-brown color, and numerous microchemical reactions gave very 

 different results for the embr3'os of the mumni}' cereals and those of 

 more recent ones. The reserve material had apparently undergone no 

 chemical change. 



In conclusion it is stated that these mummy cereals, although exteri- 

 orly in a tine state of preservation, did not possess the necessarj^ 

 organization for germination. Their reserve material had been 

 chemically unchanged and was capable of utilization b}' a viable 

 embryo, but the embryos in every case were so transformed as to be 

 without the ability to grow. This chemical alteration seems to have 

 taken place at a ver}" remote period. It is the author's expectation 

 to compare specimens of these mumm}' cereals with others less old to 

 ascertain just what changes have taken place. 



Injuries to plants by London fogs and smoke, G. Henslow 

 {^Garden, 57 {1900), JVo. 14^7, jyp. 353, 354). — -^^ account is given of 

 the injury caused by fog and smoke to plants, particularly in green- 

 houses, in the vicinity of London. The most important and harmful 

 ingredients of fog and smoke are said to be carbon, hydrocarl>on 

 derivatives, and sulphurous acid. One of the sources of injury is in 

 the deposition of carbonaceous matter on the glass whereby the light 

 is shut off. In similar ways the transpiration of the plant is largeh' 

 affected, and both mechanical evaporation and transpiration are greatl}' 

 impeded. The poisonous ingredients of fog are chiefly sulphurous 

 acid and vaporized h3'drocar])ons which pass into the houses and injure 

 the foliage of plants. The author says: "The amount of sulphurous 

 acid has been found in anah'ses in dull weather in London to be 

 ordinarih' about 6 parts per cent {<), and in a thick j^ellow fog it 

 amounts to about 20 per cent" (?). Artificial experiments with various 

 amounts of sulphurous acid in water produced precisel}' the effect 

 that was produced by the fog. The protoplasm of the plants was 

 destroyed, a decomposition of chlorophyll grains and the formation 

 of chlorophAllan taking place. Experiments with a number of hj-dro- 

 carljon derivatives have shown similar effects, pyredin causing' a rapid 

 destruction of protoplasm, a limpness of the leaves, and subsequent 

 browning. The action of these su))stances is usually first noticed upon 

 the flowers. If the buds have expanded, the flowers become checked 



