The Microscope. 105 



bend it into form C, being careful not to bend the portion b to d, 

 which should be kept straight, to fit the edge of the knife. Take a 

 strip of writing paper a little shorter than the straight portion of the 

 wire, and about three-quarters of an inch wide ; gum and bend this 

 around the wire. Bring the two edges together to form a curtain of 

 the two thicknesses of paper. This curtain should stand at an 

 angle of about 40^ from the knife. 



The curled ends of the brass clips can be turned up or down 

 so as to bring the centre of the wire b to d just over the edge of the 

 knife, and it should fit closely, but lie loosely on the edge. "When 

 we wish we can swing the wire and curtain back to admit of wiping, 

 or with one motion to the right, remove it. When we wish to 

 sharpen the knife, the clips can be slipped over the end of the blade. 



MORPHO-BIOLOGICAL CHARACTERISTICS OF THE 

 GERMS OF THE SOUTHERN CATTLE PLAGUE 

 AND THE AMERICAN SWINE PLAGUE, 

 AND THEIR POINTS OF DIFFER- 

 ENTIATION. 



FRANK K. BILLINGS. 



'' I HESE two micro-organisms are neither to be classed with 

 -■- Micrococci or bacilli. They are not round objects like the 

 former, or rods like the latter. They belong to the intermediate 

 group, to which the name "bacteria" has been given. Their longi- 

 tudinal dimensions are about twice that of their transverse. They 

 are ovoid. Their ends are rounded. If an endeavor be made to 

 differentiate these germs from one another by a microscopical 

 examination we shall find it impossible. They are approximately of 

 the same size and shape. Fresh specimens of them both will not 

 differ so much in dimensions as old cultures of either will from 

 fresh ones, or different individuals in the same old cultures. They 

 are about one- sixth the transverse diameter of a red blood-cell in 

 length. In one way, however, they can be easily differentiated even 

 by microscopical examination. The sivine- plague germ has a far 

 sharper affiniUj {its poles) for the blue and violet tinctions than that 

 of the southern cattle plague, while the latter possesses a special 

 affinity for fuchsin, which the former does not. 



W^hatever the tinction used, if applied lege artis, the ends, 

 poles, of these micro-organisms show a great specific affinity for the 

 coloring material, while the middle portion of their bodies has far 



