440 



GARDENERS' CHRONICLE 



is, to classes in agricultural colleges and in higli schools as well 

 as to the educational work of granges and other farmers' clubs. 



That there is imperative need of such instruction is suggested 

 by another quotation ; "The controllable losses of plant food on 

 American farms is fairly appalling, taken in the aggregate. To 

 give, as an illustration, the loss from only a single source, it is a 

 moderate statement, well within the limits of actual truth, that 

 one-third of the plant-food value of the manure produced by the 

 different kinds of farm animals in the United States is lost by 

 carelessness, a loss equivalent to $700,000,000 a year ; and most 

 of this enormous waste, equal in value to an annual wheat crop, 

 is pm'entablc." The need of education is suggested further by 

 calling attention to the difficulties met in choosing wisely when it 

 comes to using artificial, prepared or manufactured fertilizers 

 or manures. The names under which they are sold are so many 

 and so misleading. Lack of knowledge concerning them is apt to 

 involve great loss. With the necessary intelligence, on the other 

 hand, the user may himself put together the elements for which 

 in a form already compounded he might pay several times the 

 price. If properly informed the farmer can not only make the 

 manure produced go much further than manure, solid and liquid, 

 commonly does go but he can grow fertilizing material on ground 

 that would otherwise, at the time, be unoccupied. 



Following the treatment of farm crops as generally defined 

 there is a chapter given in detail to Garden Crops and there is a 

 chapter entitled Greenhouse Crops, Nursery Crops and Orna- 

 mental Plants, the last sub-topic being e-xcellent, as are all parts 

 of the book, but very brief, altogether too brief even for the 

 farmer in these days. The ne.xt chapter, concerning Fruit Crops, 

 is, however, a very fine one. After it comes the heading Special 

 Crops : Cotton, Tobacco, Sugar Cane, Hops, Flax, Peanuts. The 

 Appendix consists of a number of tables, carefully; elaborated, to 

 show the composition of certain fertilizing materials and of the 

 different crops. .\ complete Index makes all the items of the 

 work readily accessible. The whole is systematically and thor- 

 oughly well arranged. The many tables and illustrations are all 

 clear and impressive. 



Biology for High Schools^ by W. M. Smallwood, Ida L. Reve- 

 ley and Guy A. Bailey; 8vo., XXI + 590 pages, cloth; Allyn and 

 Bacon, Boston. 



This is a "meaty" book. It contains an extraordinary amount 

 of very useful information about matters most vital to man from 

 almost every point of view, all presented clearly and attractively, 

 in ways that in fact, it seems could not be improved upon. The 

 illustrations alone, actually totalling 439, constitute an interesting 

 course in that most important of all studies, Life, wdiat il is and 

 how to have it. Oi these illustrations a. set are of a character 

 that is novel and that might be imitated in other books of instruc- 

 tion to good advantage. This is a series of portraits of the biolo- 

 gists who have made the largest contributions tow;ard the progress 

 of the study and have done most service to mankind. Such pic- 

 lures, with the illuminating little biographies attached, stimulate 

 to worthy emulation. 



Other outstanding features, of the many commendable features, 

 are the clear and convincing mannerin which are set forth dis- 

 eases of plants and of animals, including the human animal, and 

 ways to maintain health, individual and communistic and a per- 

 vading inculcation of appreciation of the beautiful wonders of 

 created life in all its forms. .\ny boy or girl, who in the high 

 school, under a teacher of the right sort and able, might make 

 a study of this admirable work, in which the publishers have 

 successfully co-operated with their usual proficiency, would have 

 gained much indeed ; would he a far wiser and better human. It 

 would not be an cas\ task to masler, but it would be worth the 

 effort. 



A LESSON ON PLANT PHYSIOLOGY 



{Continued from fagc 437) 



It goes almost without .saying that no sample of seed is 100 

 per cent viable. Then, too, the embryos van.- in strength, or in 

 ihe amount of vitality they contain. Some w'ill begin to sprout 

 and then die, while others have not sufficient strength to push 

 their way out of the ground. These things happen even when the 

 environment is practically perfect. When some or all of the 

 conditions making up the environment are less perfect, then a 

 lar.uer proportion of viable seeds will fail to complete the act of 

 germination. 



Sometimes the plantlet exhausts the food in the seed before it 

 emerges from the soil, and of course, this is more likely to happen 

 with light seeds than with heavy ones although if seed is planted 

 too deeply, or the soil conditions are bad, it may happen in any 

 case. If the food contained in the seed is exhausted before 

 germination is complete, that is, before the shoot of the plantlet 



has come up above the surface of the ground, growth ceases, 

 because plants cannot assimilate food from outside until the 

 green substance they contain, known as chlorophyll, has been 

 formed, and the formation of this, can only take place in day- 

 light. We learn from this, among other things, that seeds must 

 not be planted too deeply. It may be argued that the shoots of 

 bulbs, tubers, and other fleshy roots, will keep on growing in the 

 dark ; this growth, however, takes place by means of the reserve 

 of plant food stored up in these bulbs, etc., in which a similar 

 chemical action goes on as in the seed. 



None of the chemical, physiological or biological changes essen- 

 tial to the development of plant food in the soil can take place in 

 the absence of the stored up energy in the soil derived from the 

 sun, and indicated by temperature, and this statment applies with 

 equal force to seeds. 



There is for seeds a certain range of soil temperature under 

 which germination is the most rapid, under which the plantlets at 

 the completion of germination are the most vigorous, and which 

 ensures the highest percentage of plants from a given number of 

 viable seeds. The seeds of different species and sometimes 

 varieties of the same species have (1) a minimum temperature at 

 which they will germinate at all; (2) an optimum temperature 

 at which germination is the quickest, and (3) a maximum tem- 

 perature beyond which germination will not take place. The 

 seeds of plants native to temperate climates will germinate at a 

 lower temperature than those from tropical species. Thus peas 

 will germinate when the soil is as cold as 32° F., while the 

 cucumber, melon, egg plant, must have one not less than 60° F. 

 String beans will germinate at a soil temperature of 45° F., but 

 pole lima beans rarely germinate at a lower temperature than 

 65° F., although it is safe to sow bush limas when the tempera- 

 ture is ten degrees lower. Seeds of the round seeded varieties 

 of peas will germinate at a lower temperature than those having 

 having wrinkled seed-cases. With sweet peas, those seeds having 

 dark colored seed-cases will come up under soil conditions which 

 may lie fatal to those with white or very light-colored seed-cases. 

 Seeds 'which will germinate at a very low temperature will not 

 do so under a very high one. Thus the embryo of peas has been 

 found by experiment to be killed when the soil temperature is 

 over 99° F.. while the ma.ximum for corn, melon, and such like, 

 is as high as 122° F. Soil conditions have much to do with 

 successful germination. In a deeply worked, thoroughly drained 

 and pulverized soil, especially if somewhat sandy, seeds invari- 

 al)ly germinate better than when the conditions are the reverse; 

 this is especially noticeable when a more or less prolonged period 

 of cold rain occurs after sowing. 



As is the case with all living organisms, the einbryo of the 

 seed requires oxygen for its development, and without oxygen, 

 even if the other conditions are right, germination will not com- 

 mence. As a matter of fact, favorable soil conditions for ger- 

 mination are such as to secure an ample supply of oxygen to the 

 ui)per part of the ground. Careful observations along lines of 

 experimentation have proved in man3- ways that when oxygen 

 is completely excluded from seeds, which are otherwise under 

 good conditions for germinating, they fail to start. It has been 

 found, too, that even after the embryo has commenced to grow, 

 if the o.xygen supply is cut off, growth ceases. A soil in the best 

 condition for germination and for the continual growth of plants 

 must permit the ready entrance of fresh air ; in other words, it 

 must be thoroughly aerated and constantly ventilated. 



It sometimes happens that after sowing, heavy rain will cause 

 the particles of soil to run together, and soon after, the hot sun 

 will cause the formation of a hard crust upon the surface, a con- 

 dition wdiich not only cuts off the supply of oxygen, but also 

 prevents the shoots, especially those of the smaller kinds of 

 seeds, from pushing through. This condition occurs more readily 

 in some soils than in others, and gives the most trouble with those 

 containing much clay and little humus. When this condition 

 has been brought about, it is advisable to carefully break the 

 crust with a fine rake, .which operation should be done as soon 

 as the surface is dry enough, .^s a preventative of this condition 

 upon soils liable to it, sprinkling sand along the rows after 

 sowing does good, and in the case of small seeds, they may be 

 covered by hand with a specially prepared sandy compost. 

 Covering the surface of the soil after sowing with sand, is also 

 a preventative of an attack of the "damping-off" fungi, and 

 should always be adopted when sowing seeds in frames or i.i a 

 greenhouse. The sterilization of sand before using it for this 

 purpose renders the effect of this safeguard the more certain. 

 Small quantities of sand may be sterilized by the use of boiling 

 water or by baking in an oven. 



Welfare work is merely applyine: the golden rule to in- 

 dustry. ^^'elfare work is good for factory, home, and 

 commnnitv. — loliii II. Patterson. 



