40 



POPULAR SCIEI^OE I^EWS. 



[Maech, 1888. 



50° and 75° are the more usual limits. In pro- 

 cesses of fermentation as the raising of bread, 

 not only is carbonic-acid gas given off, which 

 gives to the dough its lightness, but alcohol, 

 and small quantities of glycerine and succinic 

 acid are also formed. The loss of flour by the 

 fermentation of the "raising" process has 

 been estimated as high as ten per cent. The 

 old question, Where did the first baker get his 

 yeast? has never yet been answered, unless 

 we accept the theory of spontaneous genera- 

 tion, as j-east, whether plant or animal, cer- 

 tainly contains the mysterious vital principle. 



COLOR IN PLANTS. 



At a recent meeting of the Edinburgh Botanical 

 Society Mr. Sewell read a paper in which he 

 showed, according to the Gardeners' Chronicle, that 

 more or less intense color always accompanies the 

 various degrees of imperfect vegetation. Spring 

 and autumn tints come under the same explana- 

 tion as flower colors, in that there is in each case 

 a using-up of previously obtained material, not a 

 predominance of the constructive elements through- 

 out the cells. 



Coloring in connection with reproduction may 

 first be noticed among the cryptogams, where the 

 reproductive parts of the plant are yellow or white 

 their energy being spent otherwise than in produ- 

 cing chlorophyll for a vegetative function. 



Mr. Spencer and Mr. Grant Allen have both 

 pointed out that "incipient floral color is present 

 in all imperfectly developed shoots," or "might be 

 expected to appear in flowers because of their low 

 constructive energy." Evidence of this was seen 

 in caulerpa, where, though yellow when in drier, 

 less nutritive habitats, it became green when 

 grown in water, — a more nutritive condition. 

 Foliage plants, as croton or such plants as Arum 

 maculatum, have their color more intense when pot- 

 bound or growing in less nutritive places; green 

 takes the place of the color when grown under 

 more vegetative conditions, as, for instance, when 

 newly repotted by the florist. 



It is where growth is locally restricted, as in the 

 petioles of Primula sinensis, as on secreting sur- 

 faces of pitcher plants, or Drosera, or as in honey 

 glands, that color tends to appear. A similar ex- 

 planation accounts for the red tips of the daisy and 

 pyrethrum ; and for the appearance of new colors at 

 the apex of the petals, as it is in the apex rather 

 than the base or among the disk flowers that 

 growth has most certainly ceased. We may simi- 

 larly account for the predominately white color of 

 winter flowers, because at that time of year all 

 growth is sluggish: there is less actively destruc- 

 tive change from the primary yellow color. On 

 the contrary, alpine flowers, growing where there 

 is an open and sunny exposure, favoring high de- 

 structive change, are notably brilliant. Certainly 

 there are not a greater number of insects in alpine 

 than in lowland regions ; nor is the explanation of 

 white rather than red winter flowers to be found in 

 the absence of insects which would select reds at 

 that time, as has been suggested. 



Changes of color during the life of the flower, 

 as seen in Convolvulus minor or Myosotis versicolor, 

 are but gradations of the natural series of changes 

 observable with more or less distinctness as it 

 occurs in greater or less degree in nearly all 

 flowers. Such changes occur especially just before 

 death. They are very noticeably caused by al- 

 tered climatic conditions, as, for instance, where 

 a cold and damp winter has been observed to be pro- 

 ductive of white varieties, or a hot, dry summer of 



red ones. That white varieties of plants normally 

 red or blue are products of changed or weakened 

 constitution, is shown in the fact that such plants 

 as white calluna or erica may be distinguished by 

 the lighter green of their foliage, as well as by 

 their flowers. 



To explain such color variations as those of 

 Polygala vulgaris, we do not need to agree with 

 Dr. Taylor, who considers that the three colors of 

 Anemone patens, for instance, "are three kinds of 

 bait " which nature has provided, that the plant 

 may be more certain of attracting insects. We 

 may understand such varieties, if not of present 

 origination, yet to have originated under different 

 conditions of growth, which favored a more or less 

 actively destructive constitution in the petals. 



A labiate, not unlike Salvia Horminum, common 

 in Thuringia, shows all the stages of this series 

 of color-change in single plants. The flowers are 

 yellow, whilst the bracts which terminate the floral 

 axis are colored either yellow, red, or purple; the 

 purple being produced at the extremity of the axis, 

 whenever present, just at the place where, from 

 checking the growth and exposure to the sun's 

 rays, the character of the cell contents would be 

 influenced most acutely. 



Indeed, if we bear in mind these facts, agreeing 

 with the assertion made by Mr. Spencer, that floral 

 colors appear at the termination of the axis, we 

 must differ from him in his further conclusions, 

 "that this color tends to fade away, and is only 

 prevented from disappearing by the action of natu- 

 ral selection." 



More or less intense color appearing wherever 

 vegetation is checked, we must expect accumula- 

 tion of color in flowers as a necessary consequence 

 of the reduction which is there taking place. It 

 does not matter how this reduction is mainly 

 brought about, whether by use, environment, or 

 natural selection. 



We see also that colors need not be held to be 

 due to slow, indefinite variations, the cause of 

 which remains unknown: it may be a very sudden 

 variation brought about by climatic conditions, 

 which sudden variations are far more likely to be 

 noticed by insects than are very gradual changes 

 of tint. 



It does not need that we regard flower color as 

 existing alone by virtue of the benefit it confers 

 upon insects, any more than we allow older biolo- 

 gists to regard it as produced because of its moral 

 effect upon mankind. It is the natural outcome of 

 the tendency towards perfection in the reproduc- 

 tive part of the plant. It is a correlation neces- 

 sitated by the lessened vegetation ; and though 

 undoubtedly of use to insects, which check or 

 quicken the tendency to color in one case or an- 

 other, they have only taken advantage of the ten- 

 dency, which cannot thus be said to have resulted 

 solely on their account and by their selection. 



GLEANINGS. 



To REMOVE the old wood from the raspberries 

 when the ground is frozen, a good way is to give 

 a quick jerk, which will usually break them off at 

 the top of the ground. 



Scientific Tests in Hungary show that corn 

 will produce the largest yield of milk, while sor- 

 ghum will produce milk of the richest quality. 



The Phylloxera. — ^Magnesia forms a very 

 impoi-tant constituent in all soils in which the 

 French vine resists the phylloxera, and in those 

 where the American vine flourishes best. Its per- 

 centage in the ash of the American vine is more 

 considerable than in the ash of V. vinifera. Prac- 

 tical experiments are needed on the use of magne- 

 sium-ammonium phosphate as a manure for vines. 



Floating Gardens. — The floating gardens of 

 the rivers of Cashmere are formed by the long 

 sedges being interwoven into a mat, earth being 

 superimposed thereupon, and the stalks finally cut 

 under water, thus releasing them from the bottom 

 of the lake ; they are usually about twenty by twelve 

 yards in size. A dishonest Cashmere will some- 

 times tow his neighbor's garden away from its 

 moorings, and appropriate its produce, which gen- 

 erally includes cuourbitaceous fruits and vegetables, 

 and a fine description of grape. 



SooT- Water. . — The best way to make soot- 

 water is to put a couple of bushels of soot into a 

 stout canvas bag into which a piece of stone or 

 iron has previously been thrown as a sinker; then 

 tie up the bag tightly, and throw it into a tank of 

 pure water. None of the crude carbon makes its 

 escape; but by this method all the ammonia and 

 other essential component parts of the soot which 

 are really soluble are secured: and either for syr- 

 inging or watering, it is of the highest value. 



The Rabbit Pest. — The increase of rabbits 

 in Australia has, in spite of measures heretofore 

 tried for its reduction, become such as to threaten 

 the extinction of farming industry. The govern- 

 ment has offered a prize of a hundred and twenty- 

 five thousand dollars for an effective method of 

 destroying the pest. Pasteur is a candidate for this 

 prize, and his method consists in the introduction 

 of the virus of chicken cholera. Rabbits, he claims, 

 are very susceptible to this poison ; and he assumes 

 that the establishment of the disease in one of their 

 colonies would soon be followed by universal infec- 

 tion through tlie medium of the droppings. 



Cheap Irrigation for the Family Garden. 

 — An exchange commends a system of ' ' cheap 

 irrigation for the family garden," which has been 

 tested for years with increasing satisfaction : ' ' Take 

 emptied fruit-cans, place the open end on a hot 

 stove a short time to remove tlie top, punch about 

 four small holes in tlie edge of tlie bottom, set them 

 half their depth in the ground, and plant your 

 seeds around them. Fill with water or liquid 

 manure as often as need be. Cucumbers and the 

 like will take a quart can full every day it does not 

 rain. No baking of surface, no weed-seed, and 

 speed in watering, are some of the advantages." 



The Purslane Worm. .— Farmers and garden- 

 ers frequently have occasion to rejoice in the in- 

 crease of a certain class of insects, called parasites, 

 that prey upon and destroy other insects which feed 

 upon the vegetable kingdom ; but they very rarely 

 have reason to welcome vegetable-eating insects. 

 According to Professor Suow of Kansas, however, 

 that State and others adjoining are invaded by a 

 caterpillar that feeds upon the purslane weed. 

 There are few gardeners who have not had severe 

 struggles to suppress purslane. During the past 

 season the purslane worm has invaded Kansas in 

 large numbers, exciting a good deal of fear in those 

 who are in the habit of regarding all worms as ene- 

 mies of the tillers of the soil. 



A Great Place for Celery. — It is in and 

 around the fair and far-famed city of Kalamazoo, 

 says the Chicago Herald, that the celery lord, 

 with all his innate pride and odor of garlic, may 

 best be found. Here his coat-of-arms, consisting 

 of a celery penchant on a silver dollar guardant, 

 may be seen emblazoned on his armorial bearings, 

 and also on the faces of the shopkeepers. Here it 

 is that over three thousand acres of "rec^J^imed" 

 land is devoted to the cultivation of the crisp and 

 toothsome stalk that is gifted with nerve-strength- 

 ening properties. In spite of the fact that Kala- 

 mazoo leads the country in light vehicles, windmills, 

 harrows, and many other branches of manufacture, 

 she still pins her faith and liope and trust to the 

 celeiy lands and the celery lords. 



