5 2 



THE MICROSCOPE. 



mayer makes good lenses of this kind; so do Bausch and Lomb. 

 An one-and-one-half inch of Zentmayer's and a three-fourths of 

 Bausch and Lomb make a good outfit. To work nicely the gases 

 should be under heavy pressure. When the pressure in the cylinders 

 is down to 60 or 70 pounds, I do not have such good results. In 

 that condition they are generally sent to Detroit — only 40 miles 

 distant — and filled to 200 pounds pressure. 



With this simple outfit I illustrate my lectures on Histology. 

 A transverse section of the spinal cord of a pig can be enlarged to 

 ten feet in diameter on the screen. To show the nerve-cells a 

 power of 500 diameters is easily obtained. The cells will show so 

 clearly that their poles can be counted and their nuclei clearly dis- 

 cerned. Sections of injected kidney, liver, intestine, etc., show very 

 clearly and beautifully as well. Sections of cancer will show the 

 stroma and cells. Pneumonia lung will show air cells six inches in 

 diameter more or less filled with the exudate. 



One of Dr. A. Y. Moore's double-stained blood slides will show 

 the individual corpuscles and their nuclei at a distance of 20 feet 

 from the screen very clearly. This is true with a disk six feet in 

 diameter. The striae and sarcolemma of muscle can be exhibited 

 also. The circulation of the blood is simply no trick at all. I have 

 exhibited this, using the tongue of the frog, on a disk 12 feet in 

 diameter. 



By a simple device opaque specimens are thrown upon the 

 screen. In this way a frog is pithed, the thoracic walls removed, 

 and the heart beating in situ exhibited. The heart will appear 

 about a foot in length and will powerfully contract, stimulated by 

 the heat of the light. The heart may be removed from the body, 

 pinned to a card and this thrown on the screen, still there is vigor- 

 ous motion. 



Again the heart may be halved and quartered, yet still the 

 pieces will be seen to contract. No complex or wonderful apparatus 

 required. Two hundred dollars and a little patience and ingenuity 

 will go farther than some fifteen hundred dollar outfits. 



The following is clipped from last year's report of the Michi- 

 gan State Medical Society, held at Ypsilanti: 



" Dr. C. H. Stowell, Professor of Histology and Microscopy in 

 the University, was then introduced. He gave an exhibition with 

 the lime-light sciopticon with microscopic attachment, throwing 



