1897] MICROSCOPICAL JOURNAL. 359 



ment of the screw and that of the diamond carrier re- 

 quires separate and distinct operations. With the screw 

 thus connected a motion is g-iven to the diamond covering- 

 a space of about one-fifth of an inch in width. Thus 

 a screw sixteen inches long- would g-ive movement enoug-h 

 to rule a spectrum band one inch square. 



KICROSCOPICAL MANIPULATION. 



Drinking Water. — Schumburg- has thoroug-hly g-one 

 into all known methods of purifying- drinking- water, and 

 finds that bromine is the only disinfectant which can be 

 removed after serving- its purpose, without spoiling- the 

 appearance and taste of the water. The quantity of brom- 

 ine used is very small; 1 kilog-ramme is sufficient to ster- 

 ilize 16,000 litres of water. The author uses the bromine 

 in the following- solution : — Water, 100 ; potassium bromide, 

 20; bromine, 20. 0-2 C.c of this solution is sufficient to 

 sterilize in five minutes 1 litre of water from the river 

 Spree. The calcium salts or ammonia of very impure 

 river or surface water use up some of the bromine before 

 it has had time to develop its disinfectant properties. In 

 such cases enoug-h must be added to cause a slig-ht yellow 

 coloration of the water, which should last at least half a 

 minute. The 0-2 C.c. of bromine solution may be removed 

 by adding- an equal quantity of 9 per cent ammonia. — 

 Pharin. Zeitg.^ xlii., 174. 



BACTERIOLOGY. 



Baldness. — Dr. Sabouraud, in the Annales de Dermat- 

 olog-ie, firm-ly believes that the disease is contag-ious, and 

 that barbers' instruments are the most common carriers 

 of the contag-ion; but as customers come and g-o from one 

 barber to another, it is difficult to trace each case to its 

 source. Starting- with the theory of the microbic orig-in of 

 the disease, Sabouraud has worked out a strong- chain of 

 evidence in its support. He tells us that the typical hair of 

 Alopecia areata is found at the edge of an advancing- patch 



