1885.] 



MICROSCOPICAL JOURNAL. 



115 



Germicides which kill micrococci 

 and bacilli. 

 Heat — five minutes boiling- at 212'^ F 



Mercuric chloride 1-10,000 



Sulphuric acid i- 100 



Sulphuric dioxide i- 100 



Carbolic acid i- ^o 



Antiseptics which are not germi- 

 cides. (Prevent growth but do not 

 kill the organisms). 

 Sulphate of copper 1 5 "0 solution failed. 

 Sulphate of iron saturated '' '" 



Sulphite of soda •' " '' 



Sulphite of zinc " '" " 



Sulphate of zinc " '•'■ " 



Sulphite of lime 50x0 •• " 



Alcohol 95 "0 '' failed 



to kill in 48 hours. 

 Germicides which destroy spores. 

 Dry heat, 130° C. 



Moist heat. 105° C. (221"^ F.) five min- 

 utes. 



Mercuric chloride 1-1,000 



Liquor soda^ chlorinatae .... 10% 



Liquor zinci chloridi 10% 



Sulphuric acid 8% 



Nitricacid 8% 



Muriatic acid 15% 



It is a remarkable fact that sulphur- 

 ous acid, upon which so much reli- 

 ance is placed for disinfecting, does 

 not destroy spores. Even the pure 

 liquid sulphurous acid does not kill 

 the spores of anthrax. Pieces of cot- 

 ton dipped in culture-fluids were 

 placed in bales of rags to be disin- 

 fected by sulphurous acid, which was 

 forced into them. The experiment 

 failed to kill the spores. 

 o 



Discrimination of Butter and its 

 Substitutes. 



Dr. Thomas Taylor. Microscopist 

 of the Department of Agriculture, at 

 a meeting of the Washington Micro- 

 scopical Societ}', held on the evening 

 of May 26th, read a paper on some 

 discoveries he has recently made 

 while experimenting ^vith butters and 

 the various forms of butterine and oleo- 

 margarine. He first boiled a number 

 of samples of pure butter obtained 

 from Maryland, New York, Ohio, 



and other States, for the purpose of 

 crystallizing their fatty acids. After 

 a lapse of twenty-four hours, during 

 which time they were laid away in a 

 cool place to crystallize, on placing 

 small portions of each under the mi- 

 croscope, using cotton-seed oil as a 

 mounting medium, he discovered 

 that the crystals of pure butter were 

 sometimes globular and sometimes 

 elipsoidal in shape, and on turn- 

 ing the polarizer so as to cross the 

 analizer there appeared on each a 

 well-defined cross, having equal 

 arms, like that known as the St. An- 

 drew's cross, and that on rotation of 

 the polarizer the cross rotated in like 

 manner. He found also that the crys- 

 tals of butterine and of oleomargarine, 

 beef and swine fats, are of stellar form, 

 and differ from each other. These do 

 not exhibit the cross spoken of in the 

 case of true butter, and do not follow 

 the rotation of the polarizer. In this 

 way butters may be distinguished from 

 oleomargarine made of beef or swine 

 fats. 



Dr. Taylor stated that only in fresh 

 butter has he been able to detect the 

 cross in perfect form, and that in 

 butter which has been kept for some 

 time, or butter of inferior quality, 

 when boiled and viewed under the 

 polarizer, the crystals present a 

 rosette form, generally four-lobed, 

 and these rotate on the turning of 

 the polarizer as do those in fresh 

 butter — conditions not observed in 

 any other fatty bodies, animal or 

 vegetable. 



Eye-Piece Micrometers. 



For some months past, my friend. 

 Dr. M. D. Ewell, and myself have 

 been working at micrometry, and 

 the relative advantages of the eye-piece 

 and cobweb micrometers. A short 

 time ago we decided to make a series 

 of independent measurements to see 

 which method was superior. Two 

 slides of fresh blood were prepared 

 under the same circumstances, as 

 nearly as possible, the blood was 



