1886.] 



MICROSCOPICAL JOUENAL. 



79 



To THE Editor : — A friend here, who 

 has attained celebrity as a cleaner of 

 marine muds, has recently received from 

 Vienna a slide of which I think an account 

 will be of interest to your readers. The 

 design is formed on the cover-glass, and 

 consists of three hundred and forty-one 

 distinct objects placed in position with an 

 almost absolute degree of perfection, and 

 are as follows : — In the centre is an Arach- 

 noidiscus, around which are grouped forty 

 wheels of Chirodota, twenty red, green, 

 and blue-tinted diatoms {Acfiiiocychis), 

 twenty scarlet butterfly scales, alternating 

 with twenty diatoms {Siirzrcl/a), forty red, 

 green, and blue-tinted diatoms {Acfinocy- 

 chis), one hundred wheels of C/imidofa, in 

 twenty groups of five each, twenty plates of 

 Synapta, twenty anchors of Synapta, al- 

 ternating with twenty groups of diatoms, 

 three in each {Sierire//d). 



Along with this slide came a type-plate 

 of thirty-five selected diatoms of the Rich- 

 mond fossil earth, and a beautiful thin 

 section of Jutland cement-stone showing 

 many species of diatoms /;/ sittc in the 

 rock section. 



Mobile, Ala. K. M. Cunningham. 



MICROSCOPICAL SOCIETIES. 



Washington, D. C. 



Forty-first regular meeting. 



Dr. T. Taylor addressed the Society on 

 the subject of artificial butter. The speaker 

 stated that an item had recently been going 

 the round of the papers purporting to come 

 from Prof. Weber, of the Ohio State Uni- 

 versity, to the effect that the so-called St. 

 Andrew's cross, hitherto supposed to be 

 peculiar to butter, could be produced in 

 any fat by the addition of salt and water, 

 and that therefore the microscopic tests 

 for butter were valueless. 



He had had some correspondence with 

 Prof Weber, and had also received pho- 

 tographs of various fat globules, showing 

 the cross, made by Prof. Detmers of the 

 same institution, which he exhibited. As 

 he had expected, the newspapers had 

 made Prof. Weber say more than he in- 

 tended to say, and had not given the real 

 purport of his experiments. In absence 

 of full information he could not say just 

 what the scope of Prof Weber's experi- 

 ments was, but in his opinion the speci- 

 mens which Prof Weber had examined 

 consisted of various fats which had been 

 triturated with water until the mass con- 

 sisted of globules of fat surrounded by 

 thin films of water. Each globule, under 



these conditions, was a polarizing body, 

 and, accordingly, showed the cross. The 

 use of salt and water was not essential. 



But the tests for butter rest upon an 

 entirely different basis, the presence of the 

 cross being only incidental. In butter we 

 have a perfectly clear body having a defi- 

 nite structure by transmitted light. 



Prof. Weber's specimens show simply 

 a semi-solid fatty mass, structureless by 

 transmitted light. Again, if we find in any 

 given specimen, the crystals peculiar to 

 lard or other fats, that fact is enough to 

 prove adulteration, so far as the law is 

 concerned, whether the cross be present 

 or not. 



Dr. Schaeffer asked whether it would 

 be correct to assume that any fatty glob- 

 ule showing the cross must be from the 

 milk of a ruminant animal, or, in other 

 words, that such a globule must be butter. 

 Dr. Taylor replied that no such assump- 

 tion could be made. 



Dr. Taylor further stated that the cross 

 found on the globule of boiled butter was 

 peculiar to butter only as relating to the 

 stellar crystals of lard and the foliated 

 crystals of beef, employed in the manu- 

 facture of oleomargarine, and this propo- 

 sition. Prof. Weber admits — that is to 

 say, the Professor admits that butter crys- 

 tals of globose form always exhibit a cross, 

 while those of lard and beef do not. Thus 

 far he admits, in his official report. Dr. 

 Taylor's experiments are confirmed. The 

 speaker stated that the microscopic test 

 of oleomargarine had no direct relation 

 to the question of the butter crystal, but is 

 founded on the fact that normal butter is 

 not a polarizing body while oleomargarine 

 is. Therefore, when in practice, a pure 

 butter is examined under polarized light 

 and selenite plate, the only color observed 

 is that produced by the use of the selen- 

 ite. Now remove the butter and substi- 

 tute for it a slide of oleomargarine of 

 commerce, when it will be observed that 

 the color is no longer visible, but instead 

 a great profusion of prismatic colors ap- 

 pear, combined generally with the crys- 

 tals of lard. In testing oleomargarine for 

 lard crystals or amorphous fats, I examine 

 it as I find it. I do not boil it ; it is the 

 foreign fats 1 look for first. Should I de- 

 sire to know the character of the butter in 

 the compound I boil the specimen. 



Prof. Weber's first step was to boil his 

 oleomargarine ; hence, he got only butter 

 crystals, the fats were absorbed. 



Dr. Rowland showed slides of anti- 

 pyrin evaporated from alcoholic solution. 

 E. A. Balloch, Rcc. St'cr. 



