204 



SCIENCE-GOSSIP. 



INSTINCT. 



By R. Dickson Bryson, B.A., F.P.S., F.R.As.S. 



INSTINCT OF PLANTS. 



T T is proposed to offer a series of chapters on 

 •^ instinctive phenomena; and as the living and 

 the instinctive are correlated, it is necessary to 

 have some notion of what life is before we proceed 

 to discuss its qualities. Recent science identifies 

 it with physical force, and ascribes its complex 

 phenomena to a state of flux and interaction 

 between the molecules of organic structures. 

 That, of course, is mere hypothesis, and is not 

 very probable. It has never yet been shown 

 that force, chemical or electric, is correlated to 

 the living principle. Apparently the principle 

 of life is antagonistic to chemical and electric 

 force. Neither will animate a lifeless organism ; 

 all attempts, hitherto, to resuscitate 

 the lifeless have failed. 



Force is not life — infinity is between 

 them. Their functions and methods 

 are totally different. Force is con- 

 cerned with the production of ma- 

 terial, with which in its ultimate 

 essence it may be the same thing, 

 and life with its absorption. Force 

 provides and life utilizes. What the 

 two principles are in their essence we 

 cannot say. Man would fain know, 

 but the problem remains, and is likely 

 to continue unsolved. Experiment, 

 however, amply proves life to be a 

 thing of itself. 



Instinct is a property of the 

 living, and is common to plants 

 and animals. It is a habit im- 

 pressed upon the organs, which has been pre- 

 determined by the nature and. necessities of their 

 existence. Its operations are independent of will, 

 and are invariable, necessary and infallible. In 

 the animal it co-exists with conscience, in the plant 

 it does not. Though plants perform their destined 

 functions they can have no share in the prospective 

 issues involved in the process. 



Instinct is manifested in the simplest as in the 

 most complex forms of life. In the simple cell — 

 that living unit — its operations are most distinct. 

 All living structures are built up of these cells, 

 and perhaps the sum of their operations constitute 

 the whole of instinct. 



Living structures grow, and this growth requires 

 that new material be supplied ; and it is in the 

 means taken to supply this material that the 

 instinctive operations are most distinctly seen. 

 Nowhere, perhaps, is this more remarkable than 



Section of Grain of 

 Wheat. 



in the germination of a seed. Take a grain of 

 wheat. The accompanying figure represents it in a 

 longitudinal section. Observe the two coverings 

 (a and b), the outer and the inner. At the apex 

 is the awn (c) and at the base (e) the embryo ; 

 while / represents the flour, or the albumen, of 

 the seed. Examine the embryo more particularly. 

 Observe its four divisions : the young seed-leaf, or 

 cotyledon (d), the plumule, or bud, of the plant 

 (g), the root, or radicle (z), and the stem (h) 

 between the plumule and the radicle. The 

 embryo is to all intents and purposes a young 

 plant, and, like every other mortal, requires a start 

 in life. This start is brought about by a conjunc- 

 tion of the circumstances necessary 

 for its existence, viz., heat, air and 

 moisture. In the presence of these 

 elements our seed germinates, and 

 the embryo begins to grow. The 

 plumule is pushed upwards, and the 

 radicle pursues a similar course down- 

 wards. The growing plant requires 

 to be fed. The embryo thus begin- 

 ning life is helpless and delicate, and 

 would be unable to succeed in the 

 struggle for life were provision not 

 made. For this contingency the 

 parent plant has very ampl} pro- 

 vided, the flour being an abundant 

 supply for all the wants of the baby 

 plant. There is, however, a law in 

 vegetable economy, that plants can 

 only absorb food in a liquid state ; 

 and flour is an insoluble solid. This difficulty is 

 overcome by the joint action of the heat, air and 

 moisture chemically decomposing the flour. 



The process may be thus described : starch is 

 converted into sugar by the addition of four atoms 

 of hydrogen and oxygen, and these elements are 

 obtained from the moisture, H 2 0, in the atmosphere. 

 Thus : starch, C 12 , H 10 , O 10 ; grape sugar, C 12 , H 14 , 

 14 . The gluten of the wheat flour is chemically 

 identical with albumen, animal fibrine, and 

 casein, all containing nitrogen. Gluten differs 

 from starch in possessing more than one-sixth 

 of its bulk of nitrogen, an element in which starch 

 is deficient. In the ordinary domestic process of 

 fermentation, a ferment is introduced into the 

 wort by which decomposition is effected. So in 

 germination a ferment is developed which converts 

 the starch into sugar. The gluten decomposes 

 and becomes diastase, a ferment which decompose? 



