Hales (1727I 733) discussed the rotting of wounds, cankers, &c., but much had to be done with the microscope before any real progress was possible, and it is easily intelligible that until the theory of nutrition of the higher plants had been founded by the work of Ingenhouss, Priestley and De Saussure, the way was not even prepared for accurate knowledge of cryptogamic parasites and the diseases they induce.
Every plant is constrained to carry Out its functions of germination, growth, nutrition, reproduction, &c., between certain limits of temperature, and somewhere between the extremes of these limits each function finds ao optimum temperature at which the working of the living machinery is at its best, and, other things being equal, any great departure from this may induce pathological conditions; and many disasters are due to the failure to provide such suitable temperaturese.g.
It may be that in particular cases particular modes of cultivation disfavour the host; or that the soil, climate or seasons do so; but overwhelming evidence exists to show that the principal causes of epidemics reside in circumstances which favor the spread, nutrition and reproduction of the pest, and the lesson to be learnt is, that precautions against the establishment of such favoring conditions must be sought.
In the yeast cell it accumulates and disappears very rapidly according to the conditions of nutrition and is sometimes so abundant as to fill the cell almost entirely (Errera, 1882, 1895: Wager and Peniston, 1910).
But which, in consequence of imperfect nutrition, may end in mortification.
Our starting-point in this, as in all departments of biological study, must be the biological unit, and it is to the alterations to which this is subject, under varying conditions of nutrition and stimulation, that the science of pathology must apply itself.
Trophic disturbance in the nutrition of the skin may be so great that a slight degree of external pressure or irritation is sufficient to excite even a gangrenous inflammation.
Any of the abnormal conditions that bring about general or local defective nutrition is an important factor in producing fatty degeneration.
Plants need very considerable amounts of water for their nutrition and growth; the waterholding capacity is, therefore, important.
For a time after entry they multiply, obtaining the nitrogen necessary for their nutrition and growth from the free nitrogen of the air, the carbohydrate required being supplied by the pea or clover plant in whose tissues they make a home.
The blood of most species behaves differentially towards precipitants, and it is therefore conceivable that when blood is used as food and is elaborated into special compounds for the nutrition of the reproductive organs of a parasite, these specific or larger differences in the blood of animal hosts may prevent the ripening of the gonads of a widely diffused parasite and only one particular kind of blood prove suitable.
In the Principles of Sociology Spencer's most influential ideas have been that of the social organism, of the origination of religion out of the worship of ancestral ghosts, of the natural antagonism between nutrition and reproduction, industrialism and warfare.
In his Statical Essays (1727) he gave an account of numerous experiments and observations which he had made on the nutrition of plants and the movement of sap in them.
Dutrochet towards the middle of the century, and Liebig's application of chemistry to agriculture and physiology put beyond question the parts played by the atmosphere and the soil in the nutrition of plants.
It is supposed that these remarkable phenomena have gradually been evoked by difference in the nutrition of the alternating generations.
These salts are sucked up by the roots of plants, and by taking part in the process of nutrition are partly converted into oxalate, tartrate, and other organic salts, which, when the plants are burned, are converted into the carbonate, K 2 CO 3.
The variable first maxillae are seldom pediform, their function being concerned chiefly with nutrition, sensation and respiration.
The work of the leaves may briefly be stated to consist of the processes of nutrition, respiration and transpiration.
Although transpiration is a necessary accompaniment of nutrition, it may easily become excessive, especially where the plant cannot readily recoup itself.
In addition to the trophic influence exerted by each part of the neuron on its other parts, notably by the perikaryon on the cell branches, one neuron also in many instances influences the nutrition of other neurons.
Hence, when cut off from these sources, the nutrition of the neurons of various central mechanisms suffers.
But the proper nutrition of the conducting substance is indissolubly dependent on the cell branches being in continuity with the cell body and nucleus it contains.
If, on the other hand, the endosperm is the product of an act of fertilization as definite as that giving rise to the embryo itself, we have to recognize that twin-plants are produced within the embryo-sac - one, the embryo, which becomes the angiospermous plant, the other, the endosperm, a short-lived, undifferentiated nurse to assist in the nutrition of the former, even as the subsidiary embryos in a pluri-embryonic Gymnosperm may facilitate the nutrition of the dominant one.
The developing embryo at the end of the suspensor grows out to a varying extent into the forming endosperm, from which by surface absorption it derives good material for growth; at the same time the suspensor plays a direct part as a carrier of nutrition, and may even develop, where perhaps no endosperm is formed, special absorptive "suspensor roots" which invest the developing embryo, or pass out into the body and coats of the ovule, or even into the placenta.
38 first, either the marked contrast in the method of nutrition of the generally colourless Bacteriaceae to that of the blue-green Cyanophyceae is regarded as sufficient ground for to recommend it on phylogenetic grounds.
In discussing nutrition, not only is there little agreement on the nature of the solutions, there is often disagreement on the nature of the problems.
Why is civility so lacking in discussions about food, nutrition, and food policy?
First, nutrition is a very primitive science.
It is almost impossible to execute a pure controlled study of anything relating to nutrition because there are simply too many variables to consider.
And finally, consider how nutrition affects other relative and subjective factors in our lives such as energy level and mood.
This makes a great deal of sense: If nutrition isn't governed by universal laws (as physics is) and instead affects different people differently, then the way you will know certain things is by learning through trial and error, through your own experience.
I can generally tell you someone's beliefs on nutrition if you tell me what they think of green energy, yoga, SUVs, George W. Bush, alternative medicine, holistic healing, and vaccines, none of which have anything to do with food.
For instance, if you think large corporation are greedy and evil, then when you read about how large corporations produce low-nutrition food or are putting family farms out of business, you will believe it.
The subtle interplay of everything involved in nutrition is vastly more complex than our minds are able to handle.
Computers, especially computers of the future, will have no trouble handling all the variables that influence nutrition, though there will be millions of them.
And because agriculture is a technology, subject to technological advance, advances in agriculture will quicken and multiply, leading to improved nutrition and decreased hunger and famine.
So the current frustrating situation, where so many people have such wildly divergent understandings about nutrition, will fade away.
Both of these are hugely important parts of life, and I know of no one who would trade them away for a pill they swallow in the morning that gives them all their nutrition for the day.
Other businesses in the food industry—say those pricey health foods you see at fancy grocery stores—optimize for taste and nutrition at the expense of price.
And we all know about those that optimize for cost and nutrition but the resulting food tastes awful; I have consumed enough wheatgrass to attest to this.
All that we have explored in this section—rising incomes, advances in nutrition and genomics, innovations in agricultural technologies—will eventually end hunger.