78 



GLEANINGS IN BEE CULTURE. 



Jan. 15 



ly sibylline, the composition of this matter, 

 and in the severe style of physiology she re- 

 lates to you its important role. We will 

 see, however, that Poetry can gain by her 

 alliance with Science only when she cele- 

 brates the beauties of nature, which she 

 embellishes and enlarges by the luminous 

 clearness of truth. 



Let me, then, dear reader and bee-friend, 

 say something about chlorophyll, although 

 at first view this subject seems to have little 

 in common with the title of this discussion. 

 But I hope to satisfy your impatience quick- 

 ly, and reach in this manner a discussion 

 of the nectar of flowers. 



If a thin section made with a razor across 

 a plant leaf is examined under the micro- 

 scope, there may be seen in the interior of 

 the cells which compose the framework of 

 this organ, a large number of small green 

 corpuscles. It is the innumerable aggre- 

 gation of these corpuscles which gives to 

 the leaf its general tint. Each one of them 

 is a fragment of living matter impregnated 

 with a green pigment which the chemist 

 has been able to isolate and which he calls 

 chlorophyll. These microscopic organisms 

 are the agents of a marvelous phenomenon 

 to which we will call attention in a few 

 words. 



Everybody knows that plants breathe; 

 they absorb by means of small openings, or 

 stomata, with which the surface is covered, 

 the air which is to furnish to the plant the 

 oxygen necessary to every living being. 

 But this air brings also to the plant carbon, 

 a mineral absolutely indispensable likewise 

 to life, and which constitutes even the larger 

 part of the weight of the plant. This air is 

 charged with carbonic acid, which, having 

 reached the living plant- cell, is decomposed 

 into its constituent elements, carbon and 

 oxygen. The carbon remains in the plant, 

 incorporated into its living matter, while 

 the oxygen is freed. 



But in the plant how is this decomposi- 

 tion of the carbonic acid brought about, 

 this reduction, as the chemists say, the ini- 

 tial phenomenon in the assimilation of the 

 carbon? To accomplish in his laboratory 

 such a reduction the chemist is obliged to 

 develop in his crucibles an enormous tem- 

 perature. But the plant-cell is a different- 

 ly constructed laboratory where, without 

 noise, and without appreciable heat, this re- 

 duction of carbonic acid is effected by means 

 of a very singular agency, which is no oth- 

 er than the corpuscle of chlorophyll of which 

 we have spoken above. 



These corpuscles, in fact, grouped in the 

 plant-cell one next to the other, form a com- 

 pact green screen interposed among the rays 

 of sunlight and the living matter of the cell. 



In the same manner as a red or blue pane 

 of glass placed between our eyes and the 

 white light of the sun transmits only the 

 blue or red rays which constitute this white 

 light, and absorbs the others, so this green 

 chlorophj'llian screen absorbs a large part 

 of the solar radiation, permitting only the 

 green rays to be transmitted. In these ra- 



diations the luminous rays are the ones 

 which strike more particularly our senses. 

 But along with these luminous rays, others 

 are found: the heat rays, up to a certain 

 point perceptible to our senses; also the 

 chemical rays, which we can perceive 

 only by the effects they produce. It is 

 in this manner, for example, that light acts 

 on a photographic plate though its chemi- 

 cal rays, which decompose, that is to say, 

 reduce, the salts of silver with which the 

 plate is charged; and it is this radiation 

 which figures on the plate the picture of the 

 objects as a silver pencil would do it. The 

 radiation effected by the screen of chloro- 

 phyll is likewise the source of chemical en- 

 ergy, which, in the plant-cell, reduces the 

 carbonic acid; as soon as this reduction is 

 brought about, the carbon is incorporated 

 into the living matter. 



But the force of the radiations absorbed 

 through the chlorophyllian screen is not 

 emplo3ed solely in decomposing the carbon- 

 ic acid. It serves also to vaporize a large 

 quantity of water which circulates within 

 the plant, drawn constantly from the soil 

 by its roots. 



Every one knows that plants transpire, 

 that is to say, that they give ofl^ continually 

 water-vapor. Transpiration is a general 

 phenomenon with plants; it takes place both 

 by nieht and by day. But with those plants 

 which have green matter this phenomenon 

 is increas^ed by the vaporization due io the 

 chlorophyll, and this, therefore, takes place 

 only during the day. 



Clilo) ovaporization is the name which has 

 been given to this particular phenomenon 

 which adds its effects to ordinary transpi- 

 ration so as to increase the latter to a very 

 considerable degree. Ordinary transpira- 

 tion alone, in fact even accelerated by the 

 heat of the day, comprises only a small part 

 of the total vaporization. Thus, for a hun- 

 dred grams of water exuded by a single 

 wheat plant, hardly three or four grams are 

 due to ordinary transpiration; a field of 

 cabbages where the plants are set at 50 

 centimeters. 19.685 (or nearly 20) inches, 

 gives off per hectare 2 471 (or nearly 2 '2) 

 acres, under the complete influence of this 

 phenomenon during the twelve hours of the 

 day, the enormous figure of 20,000 kilo- 

 grammes (44,092 lbs.) of water. Imagine the 

 prodigiousquantity which isconstantly pour- 

 ed intothe atmosphere from the meadows and 

 forests! This surprising effect, produced by 

 such a slight cause, chlorophyll, balances 

 the absorption by the roots and keeps up 

 the continual current of water necessary to 

 the plant. 



Every evening, as soon as the sun is be- 

 low the horizon, chlorovaporization slackens, 

 then stops, whilst the absorption of water 

 by the roots continues. This, then, occur- 

 ring- withe ut being bal.inced through vapor- 

 ization, results in the internal pressure be- 

 coming more and more intense. A time ar- 

 rives when this pressure is too strong, and 

 the water escapes from the plant. This is 

 the phenomenon of exudation, or of cliloro- 



