The Microscope. 377 



that this anxiety was set at rest by showing, as some of the 

 investigators had the means of doing, that ttenial disease hap- 

 pened to be less frequent among the city folk supplied from the 

 Loch than among the country residents who had their independ- 

 ent water supplies. And, further, the thought suggests itself 

 that the parasite may not; have been the Taenia solium after all, 

 although resembling it, and it may have been, perchance, the 

 same animal, whose life-history Mr. Linton has partially set 

 forth in the fontes et fauna of our far West. 



One peculiarity of the Yellowstone Lake trout not mentioned 

 above is that the larval parasite may occur in the same fish of 

 very different sizes, from that of a small cyst not larger than a 

 small-sized shot, to that of larvse that grow in the muscular 

 tissue to be several inches in length. 



WAYS • 

 AND MEANS 



To SEE THE MARKINGS ON WOOL FIBRES.* — To make these 

 characteristic markings more prominent, so that they may be 

 readily studied, the fibre under examination must be treated to 

 reduce its transparency and slightly spread the scales upon 

 which the markings depend. To this end the fibre must first 

 be cleansed and freed from the natural grease with which it is 

 covered. This operation also effects the desired slight dis- 

 placement of the scales. The material to be used for this pur- 

 pose is a solution of silver nitrate in the strongest water of 

 ammonia. The fibre, without any previous treatment, should 

 be immersed in this solution directly, and after sufficiently long 

 digestion, removed and dried, either by exposing it to sunlight 

 or by heating on the drying plate. This whole treatment 

 causes the fibre to swell somewhat, but the distortion occurring 

 is more than counterbalanced by the results obtained. All the 

 transverse markings showing the form and arrangement of the 

 scales may be easily seen. The mounting medium is, however, 



* Keport upon an examination of wools. 



