918 SUMMARY OF CURRENT RESEARCHES RELATING TO 



study of microscopical preparations, both living and stained, by means 

 of photography, by culture experiments, inoculation, and biological 

 analysis. Following each topic is the literature pertaining to it. The 

 second part treats of the special methods used by different investigators 

 in studying anthrax, cholera, glanders, hog cholera, hydrophobia, 

 leprosy, malaria, septicaemia, syphilis, tuberculosis, typhoid fever, 

 diphtheria, erysipelas, yellow fever, &c,, each being followed by the 

 literature of the subject. The third part contains forty-six formulae 

 for the preparation of stains, reagents, culture media, &c. 



The descriptions are short and sometimes quite inadequate ; there 

 are no illustrations, which in many instances would be as valuable as 

 descriptions ; the work is evidently compiled from literature alone 

 without that fulness of detail which the author could only give from 

 personal knowledge of the manipulations ; there is no index.* 



Discrimination of Butter and its Substitutes.! — Dr. T. Taylor, 



microscopist of the Department of Agriculture (U.S.A.), records some 

 discoveries he has recently made while experimenting with butters 

 and the various forms of butterine and oleomargarine. He first boiled 

 a number of samples of pure butter 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 Microscope, using cotton-seed oil as 

 a mounting medium, he discovered that the crystals of pure butter 

 were sometimes globular and sometimes ellipsoidal in shape, and on 

 turning the polarizer so as to cross the analyser there appeared on 

 each a well-defined cross, having equal arms, like that known as the 

 St. Andrew's cross, and that on rotation of the polarizer the cross 

 rotated in like manner. He found also that the crystals of butterine 

 and of oleomargarine, beef and swine fats, are of stellar forms, 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 oleo- 

 margarine made of beef or swine fats. 



Dr. Taylor states that only in fresh butter has he been able to 

 detect the cross in perfect form, and that in butter that 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. 



In connection with Dr. Taylor's non-microscopic test,J Mr. J. B. 



* Bot. Gazette, s. (1885) p. 315. 



t Amer. Mon. Micr. Joum., vi. (1885) p. 115. Cf. alao this Journal, ante, 

 p. 356. 



X See this Journal, ante, p. 357. " The test is a very simple one. If a few 

 drops of sulphuric acid be combined with a small quantity of pure butter, the 

 butter will assume first an opaque whitisli-yellow colour, and after the lapse of 

 about ten minutes it will change to a brick red. Oleomargarine made of beef 

 fat when treated in the same manner, clianges at first to a clear amber, and after 

 a lapse of about twenty minutes to a deep crimson." 



