SMUT. 



SMUT. 



which is found in all remnants of putrefied 

 organic compounds ; 4th, free phosphoric acid, 

 amounting scarcely to more than -004 of the 

 smut ; 5th, phosphates of ammonia, magnesia, 

 and lime, "in the proportion of a few thou- 

 sandths. " We must remark," say MM. Four- 

 croy and Vauquelin, " that in one examination 

 of putrefied gluten, we found characters very 

 similar to those of the smut of wheat ; and that 

 the products of the one are so like those of the 

 other as to render it difficult, in certain cases, 

 not to confound them together. It requires a man 

 to be well practised in chemical experiments to 

 discern the slight differences that exist between 

 these two putrefied matters, because the dif- 

 ferences are only delicate shades, not easily 

 discernible. The contagion attacks especially 

 the gluten, and precedes, indeed prevents, the 

 formation of the starch ; since we know posi- 

 tively that this fecula, no traces of which are 

 found in the smut of wheat, suffers no altera- 

 tion from the septic process which so power- 

 fully attacks the glutinous substance." The 

 ravages of this disease are chiefly, though not 

 exclusively, confined to the cereal plants. Mr. 

 Kirby says it is common to wheat, oats, bar- 

 ley, and rye; and that he has seen the flote 

 fescue (Glyceria Jl titans'), and some other 

 grasses, affected with it. Barley and oats are 

 more frequently affected by it than wheat, 

 which may proceed from the latter being usu- 

 ally steeped before sowing. Wildenow, who, 

 in his Principles of Botany, 331, describes the 

 smut under the name of "Ustilago," and as 

 being a small fungus, says, "This singular 

 variety of gangrene occurs most frequently in 

 the species of Gramineae, rarely in other plants, 

 some'.imes in Scorzonera, Tragspogon," &c. 

 The ear of corn which is attacked is in gene- 

 ral totally destroyed, but sometimes the same 

 ear contains sound as well as smutty grains ; 

 and even one end of the same grain has been 

 found diseased and the other end sound. How- 

 ever, as all the grains in an ear are usually 

 infected, so, when one stalk is smutty, it gene- 

 rally happens that all the ears from the same 

 root are so too. In March or April, upon care- 

 fully opening the hose or blade (folium vagi- 

 uins) which covers the ear, and examining the 

 young ear, although it was not above one-sixth 

 part of an inch long, and almost close to the 

 roots, M. Du Hamel found this embryo already 

 black and distempered ; a fact confirmed by 

 the researches of Mr. Kirby. When the dis- 

 eased ear domes out of the above-mentioned 

 envelope, it looks lank and meager. About 

 half an inch of the upper part of its stalk is 

 commonly not quite straight. If cut asunder 

 at not more than a quarter of an inch below 

 the ear, it will be found nearly solid or filled 

 with pith; the circulation above is therefore 

 obstructed. The next most important point for 

 consideration is, from whence is the infection 

 communicated; and the following experiments 

 will be found to have demonstrated that it is 

 capable of being conveyed to the plants by the 

 agency of the parent seed. These experiments 

 are satisfactory and decisive; for, although 

 they are only in accordance with the most pre- j 

 valent opinions of farmers upon the point, yet ! 

 prevalent opinions are not ahvays in accord- ! 

 993 



ance with truth, and are never to be implicitly' 

 received until sustained by evidence, which is 

 independent of prejudice, and more accurate 

 than surmise. 



Mr. R. Somerville, in a paper published in 

 the Communications to the Board of Agriculture, 

 details experiments fully substantiating the 

 fact, that the disease is communicable to the 

 crop from the parent seed. He mixed some 

 ^mutted grains with others perfectly healthy, 

 and kept them in a box for two months ; after 

 which, previously to sowing, he rubbed them 

 together between his hands. The sample was 

 then divided into two equal parts, one of which 

 was well washed with clear water three or four 

 times, and then sown in a drill in his garden. 

 The other half was sown similarly, but without 

 being washed or otherwise prepared. The 

 blades appeared above the surface at the same 

 time, and during the first two months of their 

 growth there was no visible difference in their 

 appearance. Soon afterwards many of the 

 plants from the unwashed seed were observed 

 to have a darker and more dirty green hue than 

 those from the seed that had been cleansed 

 with water. This difference of colour by de- 

 grees became more striking, and increased 

 until' the grain was protruded from the blade, 

 at which time many of the dark-coloured plants 

 evinced symptoms of decay ; and the whole of 

 them, when fully developed, were found to 

 be completely destroyed by the smut. The 

 plants from the washed seed produced scarce- 

 ly a single diseased ear. These results were 

 not fortuitous, for the experiment afforded a 

 similar testimony when repeated the next 

 season. 



The experiments of Mr. Harrup agree with 

 the preceding. In these, wheat, consisting 

 half of sound and half of smutted grains, was 

 sown without being previously at all prepared, 

 and this produced a crop of which nearly two- 

 thirds were smutted. Similar wheat, soaked 

 for twelve hours in a saturated solution of 

 common salt, and then mixed with quicklime, 

 produced on the same soil, in the same situa- 

 tion, and in the same season, a crop in which 

 not a smutted ear could be found. 



Similar, but more extended, and even more 

 accurate experiments, were completed by Mr. 

 Bevan, and are recorded in the ninth volume 

 of The .Agricultural Magazine. They give the 

 result of his trials with various liquids as 

 steeps for seed-wheat. The wheat was grown 

 on a sandy -soil, at Leighton in Bedfordshire. 

 The columns in the accompanying table which 

 are marked A. contain the results from the 

 sound grain that was sown ; and those marked 

 B. are the results from smutted samples. (See 

 Table at top of the next page.) 



The conclusion from these and many other 

 accordant experiments is ; that washing the 

 seed is effective in preventing the communica- 

 tion of the disease to the crop to which it gives 

 birth. If the washing was frequently repeated, 

 or the cleansing made complete, by passing a 

 continual stream through the seed for some 

 hours, it is probable that simple water might 

 be employed for this purpose as effectually as 

 any saline solution. But as this would require 

 more labour than is desirable, and as the salts, 



