901 



FUNGI. 



FUJx'GI. 



of the world is by many attributed to the attack of Fungi. This 

 view has been strongly advocated by Berkeley, who describes the 

 fungus as Botrytis infestans. The spores are supposed to enter the 

 stomata and to cause disease in the leaves in the first instance, 

 which afterwards extends to the tubers. The effects produced on the 

 leaves resembled much those caused by poisonous gases, such as 

 hydrochloric, sulphuric, and nitric acids. 



" Berkeley attributes the Potato disease entirely to Fungi. He 

 states that the disease commenced in the leaves. They were attacked 

 by the mould, which ran its course in a few hours ; and from the 

 rapidity of the action, the period for examination of the leaves has 

 often passed over. The fungus generated does not live on decayed 

 or decaying matter, but is one which produces decay, and renders the 

 plants unhealthy. The fungus acts by feeding on the juices of 

 plants, preventing the elaboration of the sap in the leaves, obstructing 

 the admission of air and the emission of transpired fluids. The stem 

 is thus overcharged with moisture, and ultimately rots, while every 

 source of nutriment is cut off from the half-ripe tubers. The atmos- 

 pheric conditions during the late disease made the fungus spread 

 rapidly. 



" While there is no doubt that the Botryt!s is developed in the 

 progress of the Potato disease, the question arises whether or not it 

 is the originating cause. The view which seems to be most consonant 

 with the phenomena is, that changes are induced in the cells of the 

 potato by cultivation which render the leaves liable to disease. Atmos- 

 pheric influences are thus enabled to act upon them, so as to cause 

 alterations in their cells ; and the attack of a fungus, such as the 

 liutrylii, accelerates the morbid action, and causes it to assume a 

 peculiar form. In this way high cultivation, atmospheric influences, 

 and Funyi, all contribute to cause disease. In the Potato disease of 

 1845, Hailing says that brown granular matter was deposited in the 

 cells, first in those near the epidermis, then the cellular walls lost 

 their transparency, and the cellules could no longer be isolated by 

 boiling water ; next the cell-wall was destroyed, and small cavities 

 were formed in the midst of the tissue, in which were agglomerated 

 grains of starch, and finally parasitic organisms appeared in the 

 cavities. The vegetable parasites developed were Polyactii alba. 

 Fiuisporium Solani, F. duly mum, F. candidum, and Oidium violacewn. 

 When the disease had advanced insects were also present. 



" Crum attributed the disease of the tubers of the Potato to rupture 

 of the starch-cells, and mixture of their contents with nitrogenous 

 matter, thus causing fermentation, as in the Apple and Grape. Solly ob- 

 jects to the fungus theory of the Potato disease. He says that decaying 

 organic matter is necessary for the growth of Funyi. He thinks that 

 the disease is caused by the presence of putrifying azotised matter in 

 the stem, just below the surface of the soil ; that this is carried to 

 all parts of the plant, causes a struggle between vital and chemical 

 forces, and induces decomposition by a process of fermentation. The 

 azotised matter, in a condition to act as ferment, is produced by the 

 state of the season, by deficiency of light, and by other meteorological 

 causes. Analyses show that the constituents of the diseased potato 

 undergo a rapid and important change. Dr. Lyon Playfair and Mr. 

 Phillips found that the amount of albumen and gluten decreased from 

 2'34 in the sound potato to '32 in the diseased ; and when the disease 

 advanced they finally disappeared. 



" Mitscherlich says that the change which cellulose undergoes by 

 the action of a peculiar ferment is characteristic of the substance. 

 This fermenting agent is obtained when half putrid potatoes cut up 

 into pieces are placed in water, with portions of fresh potatoes, and 

 allowed to stand till the cells of the fresh portions begin to be easily 

 separable. It is also formed, though more slowly, when fresh potatoes 

 cut up are set aside covered with water ; the liquid is filtered, and 

 fresh potatoes, cut in slices, added to it; when these are decomposed, 

 a portion of the liquid may be treated with water, and more slices 

 of potato added, which soon become decomposed, and in this manner 

 increase the activity of the liquid. Hence, just as in the fermentation 

 of an infusion of malt, the yeast, the fermentative fungus, becomes 

 augmented, so does the ferment increase. It only acts upon the 

 cellulose, which forms the walls of the starch-cells of the Potato ; first 

 the cells separate from each other, so that it furnishes us with a con- 

 venient means of obtaining the cells with their contents in an isolated 

 state, and facilitating their examination ; the walls of the cells are 

 subsequently also dissolved, and the starch-particles fall out : in this 

 manner, in 24 hours, a slice of potato is rendered so soft to a depth 

 of two lineo that this portion can be removed by a pair of forceps, 

 the hard mass of the potato lying beneath the softened layer, so that 

 this process takes place successively from the outside towards the 

 interior ; not by the whole of the jiotato being simultaneously per- 

 meated by the ferment to the innermost portion. Exactly the same 

 process as that which we can produce spontaneously, he says, occurs 

 in the Potato disease, which during late years has done so much 

 miachief. In this also the cellulose, and not the starch, is decomposed ; 

 and the liquid, which the author had kept for a long time in contact 

 with one of the diseased potatoes, immediately produced the decom- 

 position of a sound one. This decomposition is therefore, he says, 

 nnt. the disease itself but merely the resultof it. Its cause undoubtedly 

 depends upon the dying or the previous death of the entire plant, 

 and just as it is well known in the case of other plants that they die 



when the apices of their roots are too strongly cooled, so may a sudden 

 cold rain following a long warm winter produce a similar condition 

 of the potato plant. It is only after decay has commenced that 

 Fungi and insects attack the plaut. 



" Liebig attributed the Potato disease to diminished or suppressed 

 transpiration, depending upon the hygrometric state of the atmo- 

 sphere. He refers to Hale's accurate researches in regard to the Hop 

 blight, in which the disease is traced to the want of correspondence 

 between absorption and transpiration, and a consequent stagnation 

 and decomposition of the juices. The same thing, he thinks, takes 

 place in the potato in consequence of cold and an atmosphere loaded 

 with moisture ; and he shows that in 1845 and 1846, when the disease 

 overran Europe, damp, cold, and rainy weather followed heat and 

 drought just at the period of the most luxuriant growth of the 

 potato. The vessels and cells became charged with fluids ; and, owing to 

 the checked transpiration, there was stagnation of the sap and death. 



" Fungi and putrefaction are, according to him, the consequences 

 of the death of the plant. Klotzsch proposes to check the Potato 

 disease by pinching off the extreme points of the branches and twigs 

 to the extent of half an inch downwards when the plants have 

 attained the height of six or nine inches above the soil, and to repeat 

 this on every branch or twig on the tenth or the eleventh week. This 

 check to the stem and branches, he thinks, will direct the nutrient 

 matters in the direction of the increase and multiplication of subter- 

 ranean as well as aerial branches. This leads to increased development 

 of tuber, and strengthens the leaves and stalks. Tombelle Lomba, of 

 Namur, says that he has saved potatoes from disease by cutting off 

 the stems after flowering with a very sharp sickle, and then covering 

 the ground with earth to the deptu of uot less than au inch and a 

 half. The top dressing thus applied was not disturbed till the 

 potatoes were ripe. The haulm was removed after being cut. It is 

 said that the tubers acquired a good size and were of excellent 

 quality. If these facts are true, it would appear that while leaves are 

 necessary to the development of tubers the latter on acquiring a 

 certain size can continue their growth by their own proper and 

 unassisted vitality. The general conclusions to be drawn from all 

 that has been said relative to the Potato disease are, that changes are 

 induced in the cells and vessels of the potato by certain obscure 

 meteorological and epidemic causes ; that an alteration takes place in 

 the cellulose and in the contents of the cells, which speedily leads to 

 decay ; that parasitic Funyi find a nidus in the decaying organic 

 matter, so as to accelerate and give a character to the disease ; and 

 that, as yet, no remedy has been devised." 



For an account of the Fungi supposed to produce Dry-Rot in 

 timber see the article DRY-ROT. 



In many parts of the world the Fungi afford a supply of food to 

 the inhabitants, although not more than half a dozen species are to 

 be found in the markets of London, and only the common Mushroom, 

 Truffle, and Morel are eaten iu Paris ; in Italy aud other parts of 

 Europe a large number of species are consumed. [AGARICUS.] 



Dr. Badham, in his work on the ' Esculent Funguses of England," 

 gives descriptions and drawings of the following species of British 

 Fungi as those which may be used as food : 



Ayaricus acris minor, A. alutaceus, A. atramentarius, A. campeitris, 

 A. castaneus, A. caudicinus, A. comatns, A. delicioius, A. emeticus, 

 A. erqwisitus, A. fusipes, A. heterophyllus, A. melleus, A, nebularis, 

 A. orcella, A. oreades, A. ostreatus, A. personal us, A. piperatus, A. fro- 

 cents, A. prunulus, A. ruber, A. rubescens, A. sanguineus, A. vaginatus, 

 A. violaceus, A. nrescens, A. virgineus, A. ulmarius, A. Ciesarea, 

 Boletus edulis, B. luridus, B. scaber, Cantharellus Marina, Clavaria 

 coraltoides, Fistuiiita hepatica, Helvetia crispa, H. lacunosa, llydnum 

 repandum, Lycoperdon Bovista, L. pluinbeum, Morchclla. semilibera, 

 Peziza acetabula, Polyporus corylirms, P. frondosiw, P. tuberaster, 

 Verpa digitaliformia. 



Too great caution however cannot be employed in distinguishing 

 the edible from the poisonous species. In the markets of Rome an 

 inspector of Funguses is appointed, whose duty it is to examine all 

 Fungi exposed for sale, and none are allowed to be sold but with his 

 express sanction. But it would appear, from a case quoted iu Liudley's 

 ' Vegetable Kingdom,' that Fungi which are usually iuocuous may, 

 under certain circumstances, become poisonous. The fungus con- 

 sumed in this instance by a family in Cambridgeshire was the 

 Agaricm pcrmnatus, a species sold in Uovent Garden under the name 

 of Blewitts, and which all writers agree iu regarding as perfectly free 

 from danger. 



The poisonous principles produced in the Fungi have sometimes 

 been employed in medicine, an instance of which is given above in 

 the Ergot. The action of a species of Hwista has been found similar 

 to that of chloroform. [BovisTA.] The Amanita mnscaria possesses 

 an intoxicating property, and is employed by northern uations as an 

 inebriant. The following is the account of Langsdorf, as given by 

 Dr. Greville : 



"This variety of Amanita muscaria is used by the inhabitants of 

 the north-eastern parts of Asia in the same manner as wine, brandy, 

 arrack, opium, &c., is by other nations. Such Fungi are found most 

 plentifully about Wischua, Kamtchatka, and Willowa Derecona, and 

 are very abundant ill some seasons and scarce in others. They 

 are collected in the hottest months, aud hung up by a string to dry iu 



