Tuberculosis in cattle should certainly not be forgotten.

The entire veterinary profession should be obliged to contribute their mite, especially the country practitioners.

I must most emphatically enter a protest against a "cattle commission" for any such work.

The best and most ultra-scientific veterinarian the state can procure should have charge of the work, but should do it under the auspices and control of the state board of agriculture.

Mixed commissions of one or two ordinary technical men and several civilians are of no value for scientific work.

To get a good result, the work must be first well planned, and the entire forces working must be stimulated with one purpose and controlled by one power. The state is more liable to do herself credit by adopting the above plan than by any other.

NITROGEN AND ITS SOURCES.

At a late meeting of the Massachusetts Horticultural Society, a paper on this subject was presented by that student of nature and practical cultivator, Hon. J. J. H. Gregory, of Marblehead, which is of more than ordinary value to the tiller of the soil. It strikes in the right place every time, and never misses its aim. We copy it, without stopping to ask permission.

NITROGEN IN AGRICULTURE.

The air mass surrounding the earth to a depth of nearly fifty miles is composed of about four fifths nitrogen in combination with one fifth oxygen gas. There are always right at hand unnumbered thousands of tons of nitrogen, but this vast store of potential wealth is unfortunately never available to the agriculturist. His chemistry has never yet mastered the problem of drawing upon atmospheric nitrogen for plant food. He has to depend for his supply wholly on that which has been incorporated into the structures of plants or animals. His sole resource consists in the wastes of these organic structures, in the form of excrements or of dead remains, either from land or sea. The ammoniated liquor from the gas-works is waste produced from the remains of ancient forests now consumed as coal. The same is true of animal life as of plant life. While over three fourths of the air we breathe is nitrogen, and while it enters so largely into the composition of our bodies, it appears totally inert in respiration, and enters the system solely through the organs of nutrition and in the form of vegetable or animal substances used as foods. As the product of animal decay, in drinking-water it is sometimes prejudicial to health, causing dangerous fevers. Combined with hydrogen, in the proportion of 82 parts to 18 of the latter, it becomes ammonia, one of the

most common forms in which, from the waste of both animals and plants, nitrogen is fed to our crops. It is well to fix in the mind that in changing nitrogen to ammonia, in any manure analysis, we must add about one fifth to the quantity given. The other most important form of nitrogen is nitric acid. This is a combination of nitrogen with oxygen; and nitrates, of which we see frequent mention in all works on manures, are a combination of nitric acid with soda, potash, and other materials, which are called bases.

It appears to be a settled conviction among men of science, as a result of many experiments, that plants cannot take up pure nitrogen directly from the air. The theory is, that they are able, to a greater or less degree, to get their supply through the water that carries it in some form in solution into the soil, and also indirectly from the air which permeates the soil, and under its influences yields up its nitrogen; also, there is nitrogen latent in the soil, having been accumulated there, that can be set free, to serve as plant food, by the action of certain substances, such as lime and plaster.

There is a general belief among agriculturists that plants have ways of collecting nitrogen still but little known. Some extremists have gone so far as to deny any necessity for feeding nitrogen to our crops, asserting that these can of themselves collect from natural sources all they require. There is a growing belief that their power to supply themselves from natural sources is greater than they have hitherto been credited with. It has been observed, moreover, that different kinds of plants have different capacities for taking up nitrogen. Clover is an example, for though nitrogen enters largely into its composition, it has such a capacity to help itself to the good things. that surround it that it needs very little artificial help, while wheat, though it needs but little nitrogen, is so dainty a feeder that it insists on a large artificial supply from which to pick out that little.

WHERE NITROGEN OR AMMONIA COMES FROM.-WASTE OF THE

FISHERIES.

One of the principal sources from which manufacturers of fertilizers obtain their ammonia is the fish waste or offal which they pick up all along the coast from Maine to Florida. The

chief part of this waste is from the fish known by various names in different localities as "manhaden," ""heart-heads," "mossbunkers," and in the South as "fat-backs." These are caught in nets and boiled, to secure the oil in which they are rich, at various establishments along the coast and its bordering islands. After boiling, the water and oil are pressed out of the mass, and the residue is sometimes thrown into heaps to heat and dry; at other times it is put directly into barrels and pressed in. In this condition it is known as 66 pomace," or "chum." If it is to be sold as fish guano, it is spread on large platforms to dry, after which it is ground. Fish guano is sometimes treated with acid, but whether this is done or not, it is a valuable fertilizer.

As a general rule, three barrels of fish before cooking make one barrel of the chum. The fertilizer manufacturer dries and grinds it, using it crude, or treating it with acid, to make the nitrogen and phosphoric acid directly available for plant food. Sometimes, when the catch is a large one (over two hundred thousand fishes are at times taken in a single haul of the net— enough to load two or three vessels of fifty tons each), and the quantity of fish is greater than the oil factories can take care of in hot weather, the surplus is sold to the neighboring farmers at the best price that can be got.

Besides the manhaden there are numerous other fish-wastes, all rich in nitrogen and phosphate. On two occasions I have purchased cargoes of spoiled herring; in one instance nine hundred barrels, at the rate of fifty or sixty cents a barrel, which, as a barrel weighs about two hundred pounds, would be about five dollars per ton. In some instances the fish are preserved in salt, which adds one quarter or more to the weight; in others they are fresh, with the oil in them, which does not add to their value as manure, for oil is nearly pure carbon, which is of no value for the purpose; on the contrary, it somewhat hinders their decomposition.

Occasionally, during the fall fishing, on the fishing-banks near the coast, a supply of pollock will accumulate, more than the market will take, when they can be purchased at a price that will make cheap manure. A few years ago, to help sustain the market, I left a standing order with our fishermen that I would pay twenty-five cents a hundred pounds for pollock.