EAR-COCKLE. 121 



to a state so dry that they are easily powdered, yet if mois- 

 tened with water they will at once revive. It is difficult 

 to estimate the numbers which a grain of wheat may con- 

 tain ; but when in the young state fifty thousand might be 

 accommodated in the space. When full grown the vibrio 

 is monstrous in size compared with its condition while 

 young and in the grain. The remedy for this disease does 

 not lie in merely immersing the seed in water, for al- 

 though they float at first, still they soon sink so that they 

 cannot be separated. By subjecting them to scalding hot 

 water, Professor Henslow has noticed that the vibrio are 

 killed, and suggests '* the possibility of exposing infected 

 examples to a temperature that might be sufficiently high 

 to kill these animalcules, without being so hot as to de- 

 stroy the germinating powers of the corn." 



1 6. The " wheat midge " (see fig. 1 4), is not by some consi- 

 dered an enemy of the crop worth troubling themselves 

 about -, others, however, who deem that a loss of one- 

 twentieth of a crop which has been known to be occa- 

 sioned by it is a loss worth considering, have paid atten- 

 tion to its habits and the means of preventing its attacks. 

 The "wheat midge" or fly, of which the name is " Cecidomyia 

 Tritici" may be seen collected in large numbers or clouds 

 in the month of June, between the hours of seven and 

 nine in the evening, hovering over and seeking places in 

 the wheat in which to deposit their eggs. These eggs de- 

 posited within the blossoms produce caterpillars, the larvae 

 of the midge, and which feed, their heads immersed in the 

 stigmata, according to the most plausible theory, upon the 

 juices which are secreted by the ovary, thus obstructing 

 its growth, and this whether it has been fertilised or not. 

 According to others, the caterpillars feed upon the pollen 

 after it has been shed by the anthers, thus preventing the 

 fertilization of the young seeds. Whatever be the food the 

 caterpillars feed upon, certain it is that their ravages effec- 

 tually prevent all fruitful development of the ovary, and 

 all advancement of the grain " beyond the state in 

 which it appears at the time the flower first expands." 



i 



