534 FOODS AND FOOD ADULTERANTS. 



"Blythe pattern process" arid "collision figures" is one and the same thing. Of this 

 process Mr. William L. Carpenter, in the "Journal of the Society of Chemical In- 

 dustry," of London, under date of March 29, 1S83, says: 



"In reply to Mr. Newland's inquiry on this subject, I may say that -when Professor 

 Tomlinsou first brought them forward I spent several weeks in fruitless endeavors to 

 apply the. method to analytical examination of oil, and the result, I regret to say, was 

 a complete failure." 



He has read the testimony of Mr. Hoskius given in this case in respect to his chemi- 

 cal analysis of lard. Mr. Hoskins washes out a little differently from Professor De- 

 lafontaine, but he regards Mr. Hoskm's process very much as he does that of Professor 

 Delafontaiue. He has also read the testimony of Mr. Hirsh, and will say that he 

 considers the chemical process pursued by Mr. Hirsh as the least reliable of any of 

 those referred to. Mr. Hirsh made use of the same principle that the other two 

 chemists named did, or attempted to do so. Mr. Hirsh, taking the same quantity of 

 the lard to be examined and of pure lard, and applying his process, seeks to compare 

 the residue obtained in each specimen ; that principle is the basis of the methods of 

 all these gentlemen ; the others weigh the residue obtained, which is the only possi- 

 ble way to deal with it chemically, but Mr. Hirsh measures it ; he has never before 

 heard of measuring a precipitate; that is something entirely novel and oiiginal. 



In prosecuting this investigation he tried the color test for cottonseed oil, with 

 sulphuric acid ; this consists of taking a known quantity of the specimen to be ex- 

 amined and dropping on it two drops of sulphuric acid ; with cotton-seed oil the ef- 

 fect of this combination is to produce a change of color. This method was tried with 

 cottonseed oil, with mixtures of cottonseed oil and lard, one of which was as low 

 as 10 per cent, of the oil, and with the samples 1, 2, and 3 (Fowler lard) ; in the mixt- 

 ure of lard with 10 per cent, cotton-seed oil, he could positively identify the presence 

 of the cottonseed oil, but he could not detect any evidence of it in the samples 1, 2, 

 and 3. This test depends for its success upon having the right conditions ; it is an 

 extremely delicate test, and must be made under certain conditions in order to get 

 any results at all. He has since tried the same process with another sulphuric acid 

 and failed in being able to distinguish one from the other; that experiment did not 

 prove anything to his mind. 



The subject of investigations for the detection of cottonseed oil or tallow in lard is 

 one of the most complicated with which chemists have to deal. When chemists say 

 they can not eolve such questions people are apt to laugh at them. Altogether too 

 much is expected of chemistry in some cases, and in others not enough of credit is 

 given. The subject of investigation of fats has been worked on for many years, and 

 all the methods which have been employed have been, in general, found unsatisfac- 

 tory. In the case of butter the question has, within the past ten years, been studied 

 with great care, and in consequence it is now possible to tell positively what the 

 nature of butter is; other fats have not been examined with the same care, owing to 

 the immense amount of time and labor necessary to go through the investigation 

 fully. In a general way he will say that the methods employed for determining the 

 question are unsatisfactory to him. In the case of the samples 1, 2, and 3, now in 

 question, he can say, that with the investigations he has been able to make of them 

 he has found no evidence whatever of impurity. All the tests he has applied to 

 them, so far as they have given indications, have indicated the absence of impurity ; 

 the methods being imperfect, he can not say positively that the lard is pure, but the 

 indications are all in that direction, with no indications whatever in the opposite 

 direction. 







The spectroscope develops a difference in the appearance between cottonseed oil, 

 either alone or mixed with, lard, and that of pure lard; by the use of the spectro- 

 scope ho was able to positively, and without difficulty, tell that a ct-i tain specimen, 

 unknown to him at the time, but which really contained 10 per cent, of cottonseed 



