CHAPTER IV.. Results in Proof of the Tenableness of the Proposition.

RESULTS IN PROOF OF THE TENABLENESS OF THE PROPOSITION.

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SECTION I.

OBSERVATIONS ON SOME OF THE LAWS OF EPIDEMIC DISEASES.

The results obtained by comparing certain facts connected with Epidemic Affections of animals, with analogous affections in plants, afford, from the few instances I shall here notice, a very strong presumption, that analogous causes operate in the production of these affections. I have already quoted from Hecker, to shew that previously to, and during the Epidemics of the Middle Ages, the minuter forms of animal and vegetable life appeared to be called into existence, much more abundantly than usual; that famines prevailed in consequence of failure of cereal crops, no doubt depending then, as now, upon the various forms of fungiferous growth. I cannot refrain quoting here, a passage or two from our old friend Virgil; for he confirms not only the fact of peculiar showers in {156} connexion with diseases, but he also refers to the rust of corn, thus:

150. "Mox et frumentis labor additus; ut mala culmos Esset rubigo ... ... Intereunt segetes."

Georg. 1.

Then:

311. "Quid tempestates autumni et sidera dicam?

. . . . . .

322. "Saepe etiam immensum coelo venit agmen aquarum Et foedam glomerant tempestatem imbribus atris Collectae ex alto nubes."

Georg. 1.

The occurrence of black showers in this country has been observed during the present year, and I understand that in the fenny countries of the East, the corn has suffered much from the Uredo. I am not mentioning the circumstances as cause and effect, but merely to call attention to the fact, that unusual phenomena of this kind have been generally associated with disease of the animal and vegetable tribes.

The same causes also predispose plants as well as animals, to epidemic attacks of disease. The repeated observations in the public journals on the subject of ventilation, drainage, and over-crowding, render all notice from me needless, to shew that these, though they do not produce the diseases {157} treated of, yet that under the influence of bad air, bad drainage, and over-crowding, epidemics are fostered and spread.

Lastly, says the Count Philippo R['e], "I would remark that if bad cultivation, and especially bad drainage, does not produce bunt or smut, it is certain that those fields, the worst treated in these respects, suffer the most from these diseases."

It has been remarked by many observers, that a greater fecundity has attended upon Pestilences, and this has been proved by comparison, that the births in proportion have far exceeded the ordinary limit. In juxtaposition with this observation, I will place the following, not as a proof, but as a remark made quite independently of the subject of which I am treating. "From the first the diseased ears are larger than the healthy ones, and are sooner matured. What appears singular, but which I have not, perhaps, sufficiently verified, is that the seeds are more abundant than in a sound ear."

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Now these are facts which require amplification, and if these two alone should be shewn upon an extensive field of observation, to apply not only to corn, but to other members of the vegetable kingdom, as I doubt not will be the case, though I am not fully prepared to prove it, it would be difficult to dissociate the fertility of the two living kingdoms from the operations of one and the same, or an analogous law.

The epidemic diseases of plants are both infectious and contagious, at times they are observed to be endemic only, and then depending particularly upon some local causes. This is a law of diseases which applies equally to those of men and animals. In connexion with this law is another, which, as far as I am aware, has not hitherto been noticed in connexion with plants. The potato disease, which excited so much interest and created so much anxiety for the poorer classes of society, led the Government of this country to employ the most learned men to investigate the subject, in the hope of propounding some reasons which should explain the cause of the calamity, and thereby deduce a method of eradicating the evil, or, in other words, discover a cure for the disease. Many were the opinions as to the cause of the distemper, which it were useless here to recount, but a method was suggested, to which most people, I believe, looked forward with great anticipations, and this was to obtain native seed, and to sow it on virgin soil. Was the end accomplished? No. {159} For though the seed was sown, and the plants grew, the disease still appeared among the newly imported individuals, to as great an extent, as among the native or domesticated plants.

As a parallel to this, it may be stated, that, as regards either endemic or epidemic disease, those persons newly arrived, either in a district or country where these prevail, are even more liable to them than the residents. Again, I have learned, that where the potato disease has been so bad as to render the crop almost valueless, the best plan to be adopted is, to allow the plants to remain in the earth, and thus leave such as retain their germinating powers to come up spontaneously the following year. I certainly saw one large field treated in this way, yield a crop almost without disease.

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The seasoning, in this instance, seems to bear a comparison with the seasoning of animals and man, under a variety of diseases, which for a time renders them insusceptible of another attack. It therefore does not appear so improbable, that these affections may be regarded, as Unger, the German botanist supposed, the Exanthemata, or Eruptive Fevers of vegetables.

Another feature seems to associate the Epidemics of plants and animals, in a manner suggestive of analogous causes operating in both instances.

The lungs of animals and the leaves of vegetables, are their respiratory organs, by means of which, the blood in the one case and the sap in the other, derive gas from the air, and impart gas to it, each taking what is thrown off by the other.

Now the epidemics among vegetables, have a remarkable tendency to exhibit their effects primarily on the leaves, and particularly on those parts which are appropriated to the function of respiration. It is from the stomates that many of the fungi commence to germinate, and their fructification may be seen sprouting from the opening composed of a chink, surrounded by a peculiar arrangement of cells, which constitute the breathing apparatus of their victim.

In the earlier epidemics, of which we read, one of the most remarkable circumstances, was the extraordinary influence the poisonous matter appeared to {161} exercise over the lungs, and they again, were the means of propagating the disease, and spreading the contagious particles through the atmosphere, for we read: "Thus did the plague rage in Avignon for six or eight weeks, and the pestilential breath of the sick, who expectorated blood, caused a terrible contagion far and near, for even the vicinity of those who had fallen ill of plague was certain death; so that parents abandoned their infected children, and all the ties of kindred were dissolved." "The like was seen in Egypt. Here also inflammation of the lungs was predominant." "Here too the breath of the sick spread a deadly contagion."

It is more than probable that all infectious matter obtains an entrance to the system through the lungs. Inspiring the air containing the pestilential semina is, indeed, the only plausible explanation of infection; for though the skin is indubitably an absorbing {162} surface, and capable of taking up and conveying to the blood any noxious matter applied to it, yet it is far more probable that the lungs would effect this process with greater rapidity. Then the stomach, the only other absorbing surface to which extraneous matter can be applied, is not likely to be the part where the elements of disease would obtain an entrance to the system, for many facts prove, that infectious matter may be swallowed without any injurious consequences, unless in a very concentrated state. Instances are not easily found of diseased matter having been swallowed, except where diseased vegetables have formed under some combination of circumstances, a portion of diet.

Many facts are on record which prove the powerful effect of diseased grain when made into bread, and taken for any length time as a principal article of food. The history of Ergot of Rye is too fresh in the memory of most people to require more than an allusion here. The stomach had no power over the secale, its poisonous properties were retained, after having been submitted to the digestive process, as was evidenced by the abortions and gangrenes it occasioned.

But diseased wheat is also capable of inducing {163} gangrene, and it is more than probable, that many diseases might be traced to the use of infected grain of various kinds. An interesting account of a family who lived at Wattisham, near Stowmarket, in Suffolk, and all of whom suffered more or less from living on bread made of smutty wheat, may be found in the Philosophical Transactions. The mother of this family and five of the children, consisting of three girls and two boys, all suffered from gangrene of the extremities; the father lost the nails from his hands, and had ulceration of two of his fingers. Dr. Woollaston wrote thus in a letter on this case: "The corn with which they made their bread was certainly very bad: it was wheat that had been cut in a rainy season, and had lain on the ground till many of the grains were black and totally decayed, but many other poor families in the same village made use of the same corn without receiving any injury from it. One man lost the use of his arm for some time, and still imagines himself that he was afflicted with the same disorder as Downing's family." It is not unlikely this was the case, for numbness and loss of power was one of the well marked characters of the disease.

What other afflictions may be due to diseased vegetation and adulterated articles of food, and what loss of life may accrue from cheap and adulterated {164} drugs and chemicals is hardly yet dreamt of. The systematic practice of adulteration of almost every article of diet which comes to table has become a serious question for the legislature to consider. Take only the article of milk, upon which the young children of large towns and cities, make their chief meals, with the addition of bread. How much milk comes into London from the country, how much is obtained from stall and grain-fed cows in the metropolis, and how much is said to be consumed, would be an interesting calculation. It is pretty well known that a mixture is sold by which a retailer of milk may increase his supply by one-third or one-half. It was discovered in Paris that the brains of animals, when prepared in a particular manner, formed, when mixed with a certain proportion of milk and water, a very fine and deceptive cream; in that city this system was carried on to a considerable extent. I could not help alluding to these facts while speaking of diseased grain, for who shall say to what extent a miller in a large way of business, may be able to "work in," as it is called, a considerable amount of smutty corn in the manufacture of flour? Now, as diseased grain is known {165} to induce abortion, it is impossible to tell how small a portion may in some cases produce the effect; we may therefore say with Thomas of Malmesbury, "There is no action of man in this life which is not the beginning of so long a chain of consequences, as that no human providence is high enough to give us a prospect to the end."

To return,--associated with these observations are other facts of considerable weight. Before and during pestilences, abortions are more frequent than in ordinary times; infectious and contagious diseases induce abortion; besides this, and independently of disease, conditions of the atmosphere have been known to exist when abortion has been an epidemic affection; of this Dr. Copland says, "to certain states of the atmosphere only can be attributed those frequent abortions sometimes observed which have even assumed an epidemic form, and of which Hippocrates, Fischer, Tessier, Desormeaux, and others have made mention." With this reference I will close the subject of comparison between the affections of the breathing apparatus in animals and plants, merely alluding to the probability that under some conditions of atmosphere, independently of heat, &c. vegetables without any other assignable cause will become abortive.

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