THERE are comparatively few people who are aware that we have constantly around and about us a host of al-most invisible plants that play as important a part in the economy of nature as the grasses of the field, the trees of the forest or any of the numerous forms of plant life seen in every-day walks. Botanists have named, grouped and classified these plants just as they have the more highly organized kinds. One of these groups comprises the fungi, a heterogeneous class, which includes the toad-stools, mushrooms, rusts, mildews and blights. The man who studies the fungi is now-a-days known as a mycologist. The science of economic mycology is yet in its infancy, and I may be pardoned for saying a few words in regard to the nature of the investigations a mycologist is supposed to make. Strictly speaking, an economic mycologist is one who investigates the diseases of plants caused by fungi, but as a rule the field of such an investigator is broader than this, covering a great many plant diseases not due to the foregoing cause. For this reason, I think the term "vegetable pathologist" a more appropriate one, as it does not limit the field.

Of course there is a limitation to this term, for if carried too far, we shall encroach upon the ground of the entomologist and others who have to deal with the diseases of plants caused by animal parasites. • The fungi are for the most part so small that the highest powers of the microscope are necessary to see and study them. Many live upon dead or decaying matter, hence they may be regarded as of direct benefit to man, breaking up complex chemical compounds, and in many other ways aiding him both directly and indirectly. Aside from the fungi that live upon dead matter, there is an exceedingly large class that attacks both living animals and plants, and it is with these, especially those attacking plants, that the economic mycologist has to deal. Every plant that the farmer, gardener and fruit grower cultivates is subject to the attacks of one or more of these parasitic foes. The grape alone has more than fifty of these pests, and it is a wonder that we are able to grow this choice fruit at all! More than two hundred and fifty species live upon the apple, and it is very probable that fully one-third of these are positively injurious.

To a limited degree, some of these forms are beneficial to the farmer, because they attack and frequently destroy noxious weeds. There is no doubt that many of our most troublesome weeds are held in check by this means, so that there is really a promising field here for investigation.

As we have seen that the fungi are true plants, the question may arise as to how they grow and by what means they are able to produce diseases. In the first place, it should be remembered that the fungi with which we are concerned have not the power of getting their food from the air and soil, as is the case with the higher form of plant life; consequently they must depend on other sources for it, the main one being our cultivated crops. These are attacked and their food appropriated, the results being sickness and death. The parasitic fungi, then, are nothing more nor less than robbers, and the investigations of the economic mycologist are made with a view of learning the habits of these, in order that he may determine the best methods of combatting them.

Despite the fact that these microscopic foes have destroyed our crops for years, causing annual losses of millions of dollars, no intelligent attempt worthy of note was made to investigate them until within the past ten years. Five years ago practically nothing had been done in this country toward checking their ravages; in fact, it is only during the past three years that anything like a systematic effort in this direction has been put forth. At the outset, investigators in this branch of science were beset with many difficulties, chief among which was the entire lack of knowledge on the subject among the very people the work was intended to benefit. This state of affairs was not the fault of any one in particular, certainly not that of the farmers themselves, as they could not well be expected to be familiar with a subject upon which there was practically no accessible literature. Be this as it may, however, the trouble has been a serious drawback, especially in the treatment of diseases where some knowledge of the causes at work is absolutely essential to success. It is astonishing how difficult it is to make a farmer understand what a fungus is, and how it is that such an apparently insignificant thing can make his potatoes rot, his grapes mildew or his apples scab.

With the ravages of insects it is different, for in the majority of cases the intruder can be seen at work, and the farmer has tangible evidence of what is doing the damage. Fungi, in the majority of cases, come "like a thief in the night," the farmer having no knowledge of their presence until the damage is done. Right here, let it be understood, is where we have our greatest difficulty, for it is hard to convince our friend that he must not wait until the enemy is present, but must take time by the forelock and make preparations accordingly. In other words, there is a strong tendency in all cases to resort to curative rather than preventive measures, and in consequence failure is often the result.

The Old way and the New. Fig. 1. Pear tree injured by leaf-blight. Fig. 2. One saved by treatment.

As the habits of fungi become better understood, fanners and fruit-growers show an increased interest in them. They are now discussed at many of our horticultural and agricultural meetings and, in many other ways, are more a subject of investigation than of mystery.

Laying aside these questions for the present, let us follow for a moment the progress of economic mycology from the time of its first inception in this country up to the present moment.

One of the pioneers in these investigations was Professor T. J. Burrill, of the Illinois State University, who first began to devote special attention to the subject sometime back in the seventies. At about the same time Dr. W. G. Farlow, of Harvard College, started the publication of a series of most valuable papers, which were continued up to a few years ago. Among others who contributed to the early history of this work, may be mentioned Professor Chas. Peck, of the New York State Museum of Natural History, Dr. B. D. Halsted, Dr. Chas. Bessey and others. In 1883 some work of this nature was inaugurated at the Wisconsin Experiment Station by Professor Wm. Trel-ease, and the year following J. C. Arthur, of the New York Experiment Station, began a series of important investigations which were continued for four years, or as long as Mr. Arthur was connected with the Station.