LARD AND LARD ADULTERATIONS. 525 



it is difficult to get the crystals under the microscope in perfect form ; but he thinks 

 the Board will havo an opportunity to see how perfectly they can be gotten out, by 

 an exhibition of photographs of those they have used for this examination; it is nec- 

 essary that the crystals bo washed in order to obtain a plain, clear-cut specimen. 



CERTIFICATE OF MICROSCOPIC EXAMINATION BY DU. W. T. BELFIELD.* 



CHICAGO, June 29, 1833. 



On June 12, 1833, I received from Prof. W. S. Haines three samples marked "Fow- 

 ler 1," " Fowler 2," "Fowler 3," respectively. I have submitted these samples to mi- 

 croscopical examination for the purpose of detecting the presence of beef tallow. By 

 cither 0110 of two methods I have satisfied myself of my ability to detect the pres- 

 ence of beef tallow in lard, whenever the admixture contains 10 per cent, or more, 

 by weight, of the tallow. 



By neither of these methods did I detect the presence of tallow in the samples above 

 mentioned; I am therefore convinced that these samples do not contain an amount of 

 tallow equal to 10 per cent, of the- weight. 



I havo as yet no knowledge of any methods of microscopical examination whereby 

 I can detect an admixture of less than 10 percent, of tallow with certainty, but I havo 

 never obtained in the samples above mentioned any appearances other than those 

 which may be presented by pure lard. 



WILLIAM T. BELFIELD. 



Dr. Belfiekl further says:t 



He is not familiar with the manner of manufacturing prime steam lard ; he sup- 

 poses the tanks are covered during the process of rendering and that when put into 

 tierces it is covered. If he found in a sample of lard that had been kept covered an 

 excess of cotton fibers of special characteristics he should not draw any inference as 

 to how they carno to be there; if lard in which cotton fibers wero found was chem- 

 ically tested for the determination of the presence of cotton seed oil, and the chemical 

 test was supposed to detect it, he would not be inclined to attach any more value to 

 the chemical test on account of finding individual cotton fibers in the lard by a mi- 

 croscopical examination. He does not wish to be understood as saying no one can 

 detect cottonseed oil in lard by microscopical examination ; he meant to say he could 

 not do it. He has not examined the crystals from isolated stearino or isolated palmi- 

 tine. In crystallizing stearine and palrnitine, in the manner described by Mr. Hos- 

 kius, he should think the appearance of the crystals would depend on the relative 

 proportions of each, but as he has never worked isolated palmitine he can not say 

 certainly. In the method he uses the appearance of the crystals does not depend on 

 the relative proportions of the stearine and palmitine in the mixture on which he 

 operates ; there is said to be a difference between the crystals of stearino and palmi- 

 tine. Ho ordinarily transfers crystals from the liquid to the microscopic slide by 

 means of a clean pipette; it can be done, and he has done it, by means of a clean 

 knife blade, or something of that sort. The objection to Mr. Hoskins's method is that 

 the characteristic crystals of lard and tallow are not formed by it ; there is so much 

 granular matter that it gives crystals so nearly alike that he can not differentiate 

 between those of lard and of tallow; a principle to be worth anything, in matters of 

 this kind, must detect minute adulterations. The question of discovering adultera- 

 tion in lard by microscopical examinations is a new one, at least it is so to him. New 

 discoveries of facts by microscopy, which may be subsequently well established, are 

 sometimes questioned even by experienced microscopists, if they fail to follow the 

 methods and directions of the discoverer, as has been the case in some notable in- 

 stances. These persons may attempt to follow the discoverer, but, doing so imper- 

 fectly, fail to secure the expected results. This fact, however, does not apply to his 

 judgment on the method pursued by Mr. Hoskius, because he followed Mr. Hoskius's 

 method as he described it. 



* Op. cit,, p. 17G. t Op. cit., p. 177. 



