Page:Popular Science Monthly Volume 5.djvu/781

Rh uniform system of weights and measures, must precede the introduction of an international or universal pharmacopœia, but that we are now on a footing for establishing "a unity of standard for the composition of the principal preparations of the pharmacopœias of the English-speaking people, and this notwithstanding the radical differences between the systems of weights and measures in Great Britain and in this country respectively—the expedient needed to be adopted being no other than for the United States and British Pharmacopœial authorities to unite in putting into force the rule established by the Scandinavian nations, at their international convention, held in 1865, when the pharmacopœias of Norway, Sweden, and Denmark, were unified, and which rule is, to express the relative quantities used in pharmacy in proportional parts by weight, as, e. g., two parts by any system of weight of the first ingredient, four of the second, and one of the third, etc., thus securing like relative proportions in all standard compounds."

The Colorado Potato-Beetle.—Some time since Prof. Charles V. Riley predicted that the dreaded Doryphora decem-lineata, or Colorado potato-beetle, would reach the Atlantic States in 1878, the prediction being based on the average progress eastward of fifty miles per year. But latterly the movements of this pest appear to have been accelerated, for our esteemed contributor, Dr. Samuel Lockwood, has, during the past summer, found potato-vines infested with the larvae of the genuine Colorado beetle in West Freehold, N. J. From a communication by Dr. Lockwood to the Monmouth Democrat, a copy of which, with several additional notes inserted, has been kindly furnished us by the author, we take the following account of the researches which led to the identification of the New Jersey brood with the formidable Western insect-pest. Having secured some specimens of the larvae from West Freehold, Prof. Lockwood placed them in a glass jar with a quantity of potato-leaves. They fed ravenously on these for some time; symptoms of the pupa change were then observed, and, some friable earth having been furnished, the larvae burrowed into it, and soon assumed the pupa form. In due time the perfect beetle appeared. But, as there are two species of Doryphora (D. decem-lineata and D. juncta), one of which, the D. juncta or bogus Colorado beetle, is common in the Atlantic States, and, as both are very much alike in the beetle-form. Dr. Lockwood took every precaution to avoid error in his diagnosis.

In the larva stage the difference between the two species is decisive. Larvæ of the "bogus bug" have on each side the body a row of distinct, round, black spots, while larvae of the true Colorado species have two rows of these spots on each side of the body. To make assurance doubly sure, Dr. Lockwood procured eggs from the beetles he had himself raised, and had larvae hatched from them. There was now no room for doubt, for every one of them had the double row of spots. This conclusion is concurred in by Prof. C. V. Riley.

The capacity of the Colorado beetle for reproduction is amazing. They bear three broods in one season: one female has been known to lay 1,200 eggs. Says the Canadian Entomologist: "If the progeny of a single pair were allowed to increase without molestation for one season, the result would amount to over 60,000,000."

In anticipation of this insect reaching Europe from our Atlantic States, the German Government has made thorough preparation to meet it. Prussia has adopted a system of traveling lecturers on agriculture, Wanderlehrer. Each Wanderlehrer has a district of twenty or thirty miles, and his duties are to visit the farmers personally and instruct them. Specimens of the Colorado beetle have been supplied to these teachers, so that, through their instructions, the German farmers are already well informed as to this insect, in fact, know all about it, and can recognize it when it comes. If such a thing is possible, it will be destroyed on its first appearance.

The original home of this insect was Colorado, It is known that it lived upon the mountains there over fifty years ago, and that it fed upon the Solanum rostratum, a species of wild-potato. When the white man began planting potato-patches on the Rocky Mountains, better food, and in larger quantities, caused the great increase of the insect, which immediately began spreading