330 The Microscope. 



climate prevailed in the latitude of Virginia when the richest portion 

 of this deposit was laid down. Mr. Henry Woodward, in the 

 Popular Science Review for 1877, says: "In Eocene Tertiary 

 tissues sub-tropical conditions prevailed in the latitudes of London 

 and Paris. * * * Since that period, through Miocene and 

 Pliocene formations, we trace a gradual lowering of the temperature 

 by the sub- Arctic and Arctic character of the fauna and flora. Then 

 came the glacial period. The axis of the earth has an inclination 

 to the plane of its orbit of 23|°, and it is calculated to have reached 

 an inclination of 35|° during the glacial period, which Mr. Belt 

 estimates to have occurred twenty thousand years ago, and Mr. Croll 

 two hundred thousand." 



It appears, then, that this most interesting deposit is a memorial 

 of the glacial period; and, whichever calculation we adopt, its 

 immense antiquity is evident. Looking through the tube of the 

 microscope at these fairy forms flashing with all the brilliance and 

 color of the richest gems, sculptured with geometrical lines more 

 delicate and beautiful than the finest embroidery; remembering that 

 for untold ages they have been compressed to solid rock under the 

 superincumbent weight of millions of tons of earth, sand and gravel, 

 we can but wonder at the almost miraculous preservation of so 

 splendid an evidence of the "promise and potency" of the mysterious 

 forces which surround us. 



NOTES ON PRACTICAL EXAMINATION OF MUSCLE 



FIBERS. 



V. A. LATHAM, B. SC, F. R. M. S. 



QEEING- the excellent article on the Forms, etc., of Muscular 

 ^ Fibers in the September number, I thought this collection of 

 methods of examination might prove acceptable to those who wish 

 to try the various ways and thus arrive at the best results. No 

 originality is claimed, as the methods are those collected from 

 various sources for some years, in some cases being considerably 

 modified to suit my own requirements. 



1. Harden the tissue by 95 per cent, alcohol; follow with 

 absolute alcohol ; cut sections, or tease the fibers carefully. Place the 

 sections for one minute in 25 per cent, alcohol soaked for five 

 minutes in Woodward's borax, carmine solution; then soak for 

 about ten minutes in alcohol, acidulated with 20 per cent, of H. C. L., 

 until the carmine is nearly removed from all parts except the nuclei; 



