^Z'Sli, dSTiS ^se of various Mieroscopes. 325 
The Trichina spiralis has singularly forwarded the manufacture 
of microscopes. Every physician and many other persons engaged 
in examining pork, tried to obtain a microscope as soon as possible. 
At first the manufacturers could not possibly meet the demand. 
Consequently the manufacture of these instruments has everywhere 
increased, and one can get a very good French or German student's 
microscope, amplifying 250 to 300 times, for twenty-five dollars. I 
have seen instruments with a power of 150 to 200 times for twenty 
dollars, or even less. The increasing number of instruments has 
been very advantageous to science, and I hope that the calamity of 
trichina, even now fearfully prevalent in Europe, will be compen- 
sated by a marked progress in science. 
