HOP-PICKERS OPHTHALMIA. 



279 



micro-organisms, are introduced, which may vary and modify the 

 subsequent features of the trouble. The principal signs are 

 primarily those of a mechanical irritant in this disease. The 

 employment among the operatives of glass protective spectacles, 



Fig. 71. — A microphotograph of the spinous hairs of the hop-plant. 



and the use of gloves during the operation of hop-picking, to be 

 abandoned at once on the termination of the work, together with 

 more personal cleanliness, are most important prophylactic 

 measures, though difficult to enforce. 



The following is given in Science (April 28th, 1893) as the best 

 formula for Miiller's fluid : — 



Bichromate of Potassium ... ... 2 per cent. 



Sulphate of Sodium ... ... 2 „ 



Water ... ... .. ... 96 „ 



In practice it is convenient and sufficiently exact to dissolve 2 

 grammes of each salt in t,ooo cubic centimetres of water. 



