21G The Mickoscope. 



In another column is given the details of this method. We 

 quote some of the conclusions arrived at by the experimenters : 



" We are enabled to detect with great certainty the presence of 

 bacteria, some species of which can give rise to serious disease, and 

 that the chemical analysis alone does not suflfice in cases in which 

 such organisms may be present." 



" The popular impression that water purifies itself in freezing is 

 only partly true. While some gross particles, and to a certain extent 

 materials in solution may be largely removed, the bacteria which are 

 the most important, if not the sole agents in water deleterious to 

 health, are only in part destroyed by the act of freezing." 



" Different species of bacteria possess differing degrees of vul- 

 nerability to the action of low temperatures; in some species nearly 

 all the individuals are killed by prolonged freezing in water, while in 

 other species a small proportion only is destroyed, and between these 

 extremes are other species possessing intermediate degrees of resist- 

 ing power." 



" Certain species of bacteria which are capable of producing 

 serioiis and even fatal diseases in man — the bacillus of typhoid fever 

 and the common bacterium of suppuration — are capable of resisting 

 a prolonged exposure to a low temperature with the destruction of a 

 part only of the individuals thus exposed.'* 



Of equal interest and importance to the above is a series of ex- 

 periments by Dr. Sternberg, intended to fix in a definite way the 

 exact degree of heat which is required to destroy each of the patho- 

 genic micro-organism at present known. The practical value of such 

 knowledge in disinfection after acute specific diseases can be 

 readily appreciated. The experiments have been published only so 

 far as they relate to the typhoid bacillus. From these experiments 

 Dr. Sternberg has determined that the thermal death point of the 

 typhoid bacillus is 56^ C. (132. 8^F.) We shall await with interest 

 the further publication of his observations. 



Mr. Arthur J. Doherty, of Manchester, England, to whose work 

 we have already referred, is shortly to pass through the United States 

 on his way to Australia. During his tour Mr. Doherty proposes to 

 give a series of practical demonstrations before microscopical socie- 

 ties. The following list of subjects have been selected for this 

 purpose : Animal and plant-section cutting : Single and double 

 staining ; Anatomical injecting ; Selecting and arranging Foramini- 

 fera ; Mounting in balsam and other media and without pressui'e ; 



