Seed Wheat. 



sieve until all the grains will invariably pass through. These repeated sievings give each 

 grain a chance to present its largest transverse diameter to the mesh, and so ultimately 

 to remain in the sieve and be saved in that grade if possible. This repeated sieving will, 

 however, introduce a very serious error if the meshes of the sieves be not quite accurate. 

 If, for instance, there is one mesh in a sieve that is a little larger than the others one 

 might keep on sieving until all the grains had had a chance to pass through this particular 

 mesh, in which case it is evident that the whole sample would become wrongly graded. 

 The repeated sieving is very tedious, and to really reach a stage at which no grain will 

 fail to pass, requires a very long time. It has, therefore, been the writer's practice to 

 have the samples passed through each grade sieve a certain number of times according to 

 the exactness required. Thus, in a certain instance where moderate accuracy would 

 suffice, the samples would be passed five times through. In other instances they would 

 be passed ten times through, and so on. Of course, in a given experiment all samples 

 would be treated alike. As to the size of the meshes and their accuracy, in the absence 

 of any standard an arbitrary one based on metric measures was adopted, as explained 

 elsewhere ; and to ensure accuracy the author himself made and adjusted the meshes of 

 the sieves employed, and periodically inspected them in order to ensure regularity in the 

 gradings. See pages 2 and 3, and Figs. 2 and 3. 



(2. ) A shrivelled grain is always smaller than it would have been if it had grown 

 properly, so that in the process of grading here employed such grains fall into lower 

 grades than they would have fallen into had they grown properly. From this it happens 

 that in all the comparisons here presented we have to a greater or less extent, yet often 

 to a small and insignificant extent, trials between plump and shrivelled grains, that is 

 provided there were any shrivelled grains in the samples being tested, as was usually, in 

 fact almost invariably, the case. Of course this refers to grains shrivelled from 

 whatever cause. In certain cases specially noted the cause of the shrivelled condition 

 was known, and the observations were directed specially towards the behaviour of such 

 cases. It is believed that in most cases the shrivelled condition of the grains was due to 

 a variety of causes, including all of the common causes of shrivelling. 



(3.) All varieties of wheat, and especially some of them, present grains that in com- 

 parison with their fellows are flat, and such grains pass on in the method of grading 

 here employed to lower grades than their real weight and size would entitle them to 

 occupy. On the other hand the same varieties also present roundish grains that stop in 

 higher grades than they should by strict right occupy. I think these two opposite 

 qualities may just about neutralise each other in all the grades except the highest and 

 lowest ; in these, however, it seems probable than an appreciable difference in yield is 

 caused, namely, the yield of the highest will be relatively lowered and the yield of the 

 lowest will be relatively raised. These remarks apply to normal seeds. Where the seeds 

 are much shrivelled they often pass on to the tailings, and there present themselves as 

 grains, apparently much larger than the average of the tailings on account of their 

 tendency to present to the eye their largest rather than their narrowest contour. Such 

 grains, of course, were laid out for large-sized ones, but for some reason they have failed 

 to fill out, though they may sometimes contain a good-sized embryo. I have no doubt 

 that this fact will explain to some extent the results of the comparisons between the 

 tailings and the 200 grade, in which comparisons there appears a smaller superiority of 

 the 200 than would be naturally expected, considering the results of the other comparisons. 



Shrivelled Grain. 



It is impossible to give a perfectly accurate definition of the term " shrivelled seed.' r 

 It is, nevertheless, necessary in a discussion of this subject, to make it clear what degree 

 of imperfect growth is meant by the term as used in various connections. 



What is meant by saying that shrivelled seed is poor seed or the reverse ? Probably 

 the cause of the whole discussion on the value of shrivelled wheat-seed has been the fact 

 that extremely inferior-looking seed will actually germinate and, to a certain extent, 

 grow and bear a crop. To one who does not understand the physiology of plant growth, 

 this phenomenon may seem wonderful, but to the initiated it is in no degree remarkable. 

 The fact that seed " as light as chaff " has been sown and has produced a crop of grain 

 has, nevertheless, given rise to considerable surprise, a good deal of discussion, and,, 

 unfortunately, much wrong practice. 



From this it follows that the term " shrivelled seed," as sometimes used in this con- 

 nection, means seeds that are much shrivelled, so shrivelled as to be easily blown away 

 by the wind. I .do not, however, confine the term in this manner. By shrivelled seed, I 

 mean seed that is in any marked degree shrivelled ; >and in order to give the discussion, 

 more definiteness, drawings of seeds variously shrivelled are inserted (see p. 1), and 

 these are referred to in the text in such a manner as to render mistake .unlikely. 



