THE MICROSCOPE. 91 



Preservation of Protozoa. — Henri Blanc recommends pre- 

 serving protozoa with a mixture of 100 pts. concentrated solution of 

 picric acid, 2 pts. sulphuric acid, and 600 pts. distilled water, with 

 one drop of 1 per cent, acetic acid for every five centimetres of the 

 mixture. For coloring use 5 grms. of safran dissolved in 15 grms. 

 absolute alcohol, which is allowed to stand for a few days, and then 

 be filtered. — Science. 



Colors of Feathers. — In continuation of previous communi- 

 cations Dr. Hans Gadow discusses the colors which are not the 

 result of pigments: blues he considers to be the result chiefly of a 

 series of fine lines on the walls of the prism cells; greens as the 

 result, most often, of decomposition of light from a yellow pigment; 

 metallic feathers are considered to work on the simple principle of 

 a prism. — Science. 



Professor Owen, in the Proceedings of the Zoological Society 

 of London for 1882, p. 571, objects to the current statement that 

 Hilton was the first to discover the Trichina spiralis, and points out 

 that Hilton saw only the calcified cysts in the muscles of cadavers. 

 To Professor Owen himself properly belongs the honor of the 

 important discovery of the parasitic worm — a discovery which has 

 led to the prevention of so much suffering by having guided us to 

 the means of avoiding trichinosis. — Ex. 



Destruction of Red Blood Corpuscles in the Liver. — It 

 has long been supposed that the red blood globules were to a great 

 extent broken up in the liver, giving rise, among other things, to 

 the bile pigments. The experimental proof, however, has been 

 unsatisfactory. R. Nicolaides finds on careful enumeration, by 

 Melassez's method, of the corpuscles in blood drawn from the postal 

 and hepatic veins of rabbits, dogs, and cats, that the number is 

 always much less in the hapatic vein. — Archiv. de Physiol., x. 1882. 



Microscopic Animals in Bricks. — The weathering of brick 

 walls into a friable state is usually attributed to the action of heat, 

 wet, and frost; but from recent observations of M. Parize, the real 

 destroyer is a microscopic creature, and the action played by the 

 weather is only secondary. He has examined the red dust of 

 crumbling bricks under the microscope, and found it to consist 

 largely of minute living organisms. A sample of brick dust taken 



