1889.] MICROSCOPICAL JOURNAL. 189 



MICROSCOPICAL SOCIETIES. 



San Francisco, Cal. — C. P. Bates, Secy. 



May <?, i88g. — Among the visitors present were A. W. Craig and 

 W. E. Brainbridge. The latter gentleman gave a good description 

 and exhibited samples of a remarkable find located by him in Ventura 

 county, near the head of the Sespe river. It consists of what is called 

 " gem sand," which, when examined with a power of about fifty 

 diameters, is seen to consist largely of garnets, zirconite,, and what 

 parties to whom the material was submitted in the Eastern 'States pro- 

 nounced to be diamonds. The gems, to be sure, are small, appearing 

 only the size of a rape seed when magnified fifty diameters, but the 

 presence of such quantities of minute stones surely indicates the exist- 

 ence of larger members of the same family. Mr. Brainbridge remarked 

 that he had no doubt thrown away numbers of the larger stones, think- 

 ing them loose quartz crystals, as he was only panning out the sand to 

 find gold or large garnets. 



Professor Hanks, who has made a close study of the gem, stated that 

 the small stones said to be diamonds had all the characteristics of the 

 California diamond. The metal platinum is also present in this sand, 

 but whether in quantity sufficient to make it of commercial importance 

 has not yet been ascertained. The zirconite occurs in square prisms 

 with pyramidal terminations, and the stones are of a light-brown color 

 and very transparent. Altogether, the discovery of Mr. Brainbridge 

 is a remarkable one, and its future investigation will be watched with 

 great interest. It might be mentioned that the sand, of which samples 

 were shown, extends over a space of one-half to three-quarters of a 

 mile wide by several miles in length. 



Mr. Wickson exhibited a peculiar entomological phenomenon — the 

 common aphis attacked by the " Fly cholera," or, Empusa muscce. 

 The gentleman explained how the fungus spores lodge on or become 

 attached to the body of a fly, immediately commence growing, and 

 penetrate through the skin. Once inside, the spore rapidly increases 

 by self-division, in the manner of yeast cells. The first stages of the 

 disease is indicated by the restlessness of the attacked flies ; they soon, 

 however, become weak and slow in their motions. Having securely 

 fastened themselves with their broad tongues to the object upon which 

 they happened to be when attacked by the last stages of the disease, a 

 succession of spasmodic tremors pass through their wings and legs 

 and they stiffen themselves out to fly no more. The abdomen of the 

 victim of this disease, previously already swollen, becomes more and 

 more distended, and a fatty, whitish substance pushes through the softer 

 membranes between the chitinous rings or segments. Soon after a 

 whitish halo of spores is formed around the dead body, readily seen if 

 the fly happens to have fastened to the glass of mirror or window-pane. 

 These spores gradually cover the whole insect with a white dust, and 

 they appear in ever-increasing numbers as the body of the victim dries 

 up, until at last its whole interior is empty and only a shell remains. 

 From an examination of the affected aphis there appeared no reason to 

 doubt but what the fungus developed and ran its course the same as in 

 the fly, their bodies being distended and surrounded with the white halo 



