28 THE AMERICAN MONTHLY [Jan. 



ing' g"erms. There remain in the apparatus, then, inferior 

 oxidesof mang-anese, which hasten to re-oxidize themselves 

 and furnish ag"ain a certain quantity of mangfanese dioxide; 

 the water as thus finally purified contains a little lime in 

 the form of bicarbonate and traces of oxyg'enated water, 

 A very small quantity of calcium permang-anate is used in 

 this process, and, if practicable on a larg-e sceile, is of g-reat 

 importance. Water having- 100,000 colonies of microbes 

 can thus be purified, it is stated, and ice placed in water 

 with calcium permang-anate is also quickly sterilized. — 

 American Urug-g-ist. 



BACTERIOLOGY. 



TheMicrobic Character of Acute Catarrhal Otitis Media. 



— Lannois concludes from his observations that: 1. The 

 normal middle ear in animals acts like an aseptic cavity 

 and contains no micro-org-anisms. 2. The liquid of catarr- 

 hal otitis media does or does not contain microbes, accord- 

 ing- to the period at which it is examined after the beg-in- 

 ning-. 3. The disappearance of the microbes is sometimes 

 probably due to the bactericidal power of the mucous mem- 

 brane and the mucus. 4. The bactericidal action explains 

 why the secretion rarely becomes purulent, even after 

 paracentesis and repeated catheterization. 



MICROSCOPICAL SOCIETIES. 



Sheffield Microscopical Society, 

 Friday, December 18th, Mr. G. T. W, Newsholme, 

 Honorary Secretary, in the chair. — The President, Mr. A. 

 H, Allen, lectured on "The Philosophy of the Microscope." 

 He explained that he had chosen that subject because some 

 people were at sea as to the optical principles involved in 

 the use of the microscope. He reminded the g-athering- 

 that we do not see lig-ht in the ordinary sense, but perceive 

 it when it falls on something- capable of reflecting- it, and so 

 reaches the eve. Another principle fo which he called at- 



