18 



It has been pointed out that among the lower animals, a sudden 

 check to growth increases reproduction. I wish to expand that state- 

 ment into the much broader and more widely applicable generalization 

 that a decrease in nutrition during the period of growth of an organism 

 favours the development of the reproductive parts while abridging the ve- 

 getative parts. The converse, that an increase in nutrition favours the 

 vegetative parts while abridging the reproductive parts, is equally 

 true. 



Unimpeachable statistics are not abundant, for experiments bearing 

 directly upon the problem have not been undertaken, and serviceable 

 data culled from the supplementary records of other experiments are 

 not very complete or numerous, Enough are obtainable, however, to 

 lend very material aid toward establishing the generalisation. 



The cultivator employs no method so frequently for enhanoing the 

 value of his harvest as increasing the fertility of the soil. It is a 

 method of giving the plants a greater supply of nutriment, whereby 

 they grow larger and yield more. If the piinoiple just stated holds 

 true, however, the increase will be greater proportionally for the stems 

 leaves and roots than for the seeds and fruits. The data provided by 

 Latta from experiments conducted in Indiana bear this out. Wheat 

 grown upon fertilized and unfertilized areas averaging the results of 

 three seasons, 1H89-91, showed a decided gain in both straw and grain 

 due to the richer soil but upon examining into the relative inorease of 

 straw and grain it is very evident that while the increase in yield of grain 

 was considerable, it was by no means so great a9 the increase of straw, 

 and that the proportion of straw to grain was, in spite of the increased 

 yield, in reality lessened. (See Table L, page 23.) Essentially the 

 same results are evident in data obtained by Caldwell in Pennsylvania 

 with corn, averaging the results of ten years, 1881-90, (omitting 1887, 

 the crop being destroyed by insects.) (See Table II.) 



A very different method of increasing yield is the treatment of seed 

 grain before sowing to a short bath in hot water. It is especially in- 

 teresting to find that this method develops the same reciprocal rela- 

 tions between the vegetative and reproductive parts of the harvest as 

 in the preceding cases. In a crop of wheat (see Table III) thus 

 treated it, was found that while the total weight of straw and grain 

 was both as a whole and separately increased by the hot water treat- 

 ment, the yield of grain was lessened as compared with the yield of 

 straw. 



If we turn from the statistical method of demonstration and appeal 

 to general observation, an overwhelming array of facts can be brought 

 to bear. It is a common observation that plants in too rich soil run 

 to leaves instead of fruit. Every farmer knows that he can expect 

 little or no grain from an excessively rich spot of ground, although 

 the plants grow far taller and larger. The orchardist root-prunes his 

 trees to bring them into bearing, when they prove to be unusually 

 backward ; thu florist permits his plants to become pot-bound to in- 

 duce them to flower more freely; certain slow acting diseases, e.g, 

 peach yellow, and cotton rust, increase and hasten the fruiting A 

 wide range of such general facts could be cited, familiar to every one 

 having experience in such lines. In this connection Professor Atkin- 



