February 13, 1889.] 



Garden and Forest. 



81 



fact that many organic matters containing nitrogen are de- 

 composed by the action of minute organisms into nitrous and 

 afterwards nitric acids. This process of nitrification, as it is 

 called, probably takes place whenever the ammonium com- 

 binations in manures are placed upon arable soil. There are, 

 however, a few organic combinations of nitrogen which are 

 not decomposed in the soil in this manner — for instance, 

 scraps of tanned leather. These remain unaffected even 

 after long periods of time. 



With regard to the difficult inquiry as to whether any plants 

 whatever can make use of the free nitrogen of the atmosphere, 

 we have the results of many careful investigators who have 

 been impressed by the peculiar relations of Peas, Beans, 

 Clover and other plants belonging to the natural order 

 Leguminosas. In comparing Cereals, like Indian Corn and 

 Wheat, with Peas and other leguminous plants, Professors 

 Atwater, Hellriegel and others have found some interesting 

 and puzzling facts. For instance, in experiments by the latter, 

 plants of the Grass family were found to require a generous 

 supply of some salt of nitric acid, in order to grow thriftily 

 and yield a satisfactory amount of grain. But when Peas were 

 cultivated under similar conditions, there was a distinct 

 increase in the amount of nitrogen in the plants above that 

 which was suppUed to the plants during the experiments. 



Recent observations have shown that certam leguminous 

 plants possess on their roots tubercles, which are alleged to 

 contain minute gemmules belonging to the vegetative threads 

 of a fungus. By some, these organisms have been termed 

 bacterial forms, and they are thus described by one of the 

 most assiduous investigators of the subject, but the later 

 conception is, that instead of being bacteria they are yeast-like 

 gemmules. Be that as it may, it is highly probable that these 

 organisms have the power not only of breaking up nitrogen- 

 ous matters, but the far more extraordinary power of effecting 

 combinations of the nitrogen of the air which has been ab- 

 sorbed by the soil, and thus placing nitrogen combinations 

 directly within the reach of the roots of the plant. And it is 

 even suspected, upon good grounds, that the fungal forms 

 may assist in effecting absorption of other substances from the 

 soil, and thus play an important part in all root absorption. 

 Among the more recent observations of interest in regard to 

 this matter is the curious discovery that although nitrogen 

 compounds may and probably do easily escape from the soil 

 Mdiere they occur, there is, in some instances at least, a 

 marked increase in the amount contained in the soil, which is 

 ascribed with plausibihty to the presence therein of similar 

 micro-organisms unconnected with the roots of plants, by 

 which the free nitrogen of the air in the soil is brought into 

 combination. But in what way this combination is brought 

 about is not yet satisfactorily explained by any hypothesis yet 

 proposed. 



The amount of combined nitrogen brought down by rain 

 and the like has been variously estimated, but the problem 

 presents peculiar difficulties, since the observations must 

 cover long periods of time. Moreover, there are local condi- 

 tions which must necessarily modify results, and hence it is 

 manifestly unwise to rely on observations taken at any one 

 point. The most trustworthy results are probably those made 

 at Rothamsted, in England, which have been extended over 

 many years. To be sure, the determinations have not always 

 been made by the same methods, but, this aside, the general 

 results may be relied upon. The following are among the 

 estimates furnished by this station : 



1. "The nitrogen existing as nitric acid and ammonia in the 

 rainfall of one year is not far from 3.3 pounds per acre. The 

 proportion of this calculated as ammonia is between 2.3 and 

 2.6 pounds per acre, the rest being given as nitric acid." 



2. "We may probably take 4.5 pounds per acre as the best 

 estimate we can at present give of the total combined nitrogen 

 annually supplied in the Rothamsted rainfall." 



It will be seen from the above estimates that the amount of 

 combined nitrogen falling in rain-water is far too small for the 

 demands of our cultivated plants, and hence, in the case of the 

 latter, manures must be supplied. 



Concerning the destination of the nitrogen compounds 

 taken into the plant, observations have been numerous, but 

 the results are not wholly accordant. The statement given 

 below represents perhaps as well as may be, the present con- 

 dition of knowledge in regard to the matter, but it must be 

 understood that much of what follows is conjectural. The 

 nitrates or nitric acid absorbed by the roots are changed in the 

 plant into ammonia compounds which unite with the eariiest 

 formed carbohydrate (in the leaf probably) to constitute the 

 proteid or albuminoid compound. In the formation of this 

 there is also a trace of sulphur required. This union of nitro- 



gen is not, however, confined to foliage alone ; it may be sup- 

 posed to take place in any active cell. 



The nitrogen compounds thus formed in the plant are of 

 various kinds. The principal ones are chemically termed al- 

 buminoids, and resemble in many of their properties the white 

 of egg (whence their name). In amount these compounds 

 differ in different plants, in different parts of the same plant, 

 and in the same part at different seasons of the year. The fol- 

 lowing percentages are cited from a trustworthy source : * 



Red Clover, in full blossom, 3.7 



Carrot-root, 1.5 



Carrot-leaves, 3.2 



Winter Wheat 13.0 



Field Beans 25.5 



Of these amounts about 15 or 16 per cent, may be reckoned 

 as nitrogen. 



Besides the combined nitrogen, there is always to be found 

 a small amount of free nitrogen in the intercellular spaces, and 

 dissolved in the cells of plants. 



It is yet uncertain in exactly what way the nitrogen com- 

 pounds in the plant are finally broken up. The course has 

 been traced out in a few instances, which can better be exam- 

 ined in another paper of this series, when we glance at the 

 numerous changes which organic matter, as a whole, under- 

 goes while in the plant. George Lincoln Goodale. 



Cambridge, Mass. 



Correspondence. 



The Yosemite Valley. 

 To the Editor of Garden and Forest : 



Sir. — Your editorial in Garden and Forest of January 2d 

 on the Yosemite Valley interested me very much, as I passed 

 one of the pleasantest weeks of my life there only last May, 

 and if it is allowed to an Englishman to cridcise, I should like 

 to give my impressions of the present system of management 

 in the valley. I have been all over Europe and a good deal 

 of India and the United States, and I certainly have never 

 seen a spot, except the Yellowstone Park, so well worthy of 

 being preserved forever in a state of nature as the Yosemite. 



I quite agree with you that the system of leasing the park to 

 a company who have practically an absolute monopoly, both 

 of the means of conveyance and the hotels of the valley, is 

 not, in some respects, a good plan, and though I cannot speak 

 too highly of the civility and excellent accommodation we 

 received, and the goodness of the horses, drivers and car- 

 riages suppHed by this company, yet you feel all the time 

 that you have got to do as they like and not as you would like 

 yourself. The present system is all very well for travelers 

 who wish to be put through, in a large party, in five or six 

 days, andto see the regulation sights at the regular hours, and 

 who are able and willing to pay about $100 for it; but for trav- 

 elers who, like myself, prefer not to be herded with a number 

 of other more or less congenial companions, and who, either 

 on horseback, on foot, or in a small party of two or three in a 

 carriage, wish to go their own way at their own time, the sys- 

 tem is not at all suited, and many, I am sure, are deterred 

 from going there on account of this monopoly. Why should 

 it not be possible for the Commissioners to allow outsiders, 

 under proper regulations, to take their own, or other people's 

 hired horses and carriages, into the valley, without having 

 to pay fabulous sums for tolls and fodder ? And why should 

 not a little more of the open competition, which is always so 

 advantageous for those not in the ring, be allowed } With 

 regard to the fencing and cultivation which is going on, it 

 must be remembered that it would be very difficult and costly 

 to faring hay for so many horses from a distance, if none is cut 

 in the valley. 



It is not only the valley itself which needs conservation and 

 protection from the depredations of sheep, cattle, cutting and 

 burning, but also the magnificent range of forest which 

 extends from a little beyond Grants all the way to Wahwona 

 and on to the valley. Though I have seen the finest forests in 

 the Himalaya, Mexico and the Alps, the drive through this 

 unequaled coniferous timber filled me with almost as much 

 wonder and delight as the valley itself. At present it is intact, 

 or nearly so, and it may not be too late to take measures for 

 keeping it in a state of nature; but if once settlers and lumber- 

 men get in, half the beauty and pleasure of the Yosemite trip 

 will be destroyed, and California will have lost forever what is 

 now a unique pleasure ground. 



The efforts of Garden and Forest to bring the people of 

 the United States to a sense of the value of their forest prop- 

 erty are worthy of the very highest praise and support. I have 



*The tables in Johnson's " How Crops Grow," 1868, 



