Sterile Forms Research Articles

An Important Entomogenous Fungus

In I896, H. J. Webber discovered a parasite of the citrus whitefly and described its sterile form under the name of Brown mealy-wing (2). It is now popularly known by the orange growers of Florida as the Brown fungus of the whitefly. The spread of this on whitefly larvae,(I) by means of superficial hyphae that spread over the surface of the leaves attacking every whitefly larva in their way, and (2) by means of spore-like aggregations of cells that may be carried in the air or by insects,-make this one of the most important parasites of the whitefly! This and the red (Aschersonia Aleyrodis) are being introduced by orange growers into many localities in Florida with the belief that they are the most economic means yet discovered of keeping the whitefly (Aleyrodis Citri) under control.

BEHRING'S NEW REMEDY FOR TUBERCULOSIS.

The summary by Dr. Klebs, in this issue, of Behring's address at the International Congress for Tuberculosis gives us as clear an idea as at present attainable of the real gist of this matter. Shorn of bewildering detail and ambiguities, Behring's method consists in the use, for protective and curative purposes, of certain otherwise harmless constituents of the tubercle bacillus. The method appears to be a natural outgrowth of the successful immunization of cattle against bovine tuberculosis by means of injections of human and other varieties of tubercle bacilli. The introduction of living tubercle bacilli into human beings is not practicable and consequently it became necessary to try to secure the immunizing and possibly also curative substance or substances in sterile form, and this it is that Behring indicates that he believes he has succeeded in doing. In this work Behring follows paths already broken in the efforts to obtain

The Logic of Weismannism

SOME time ago, when I read an account of Prof. Weismann's experiment on the larvæ of blow-flies, as described in his Romanes lecture, a criticism of it occurred to me, which I have, recently communicated to Mr. Herbert Spencer. This was that in the experiment the quantity of food (flesh) was diminished, while the nature of it remained the same; whereas in the case of bees it is well known that the difference between the food of the worker larvæ and the royal lavæ is one of quality, not of quantity. The royal food is pollen, and is highly nitrogenous, while the food of the worker larvæ is chiefly honey. In the case of Termites, Grassi has found that the fertile individuals are fed during development on the secretion of the salivary glands of other individuals, while the sterile forms are supplied only with macerated wood-dust.