368 Dr. R. D. Thomson on Pegmine and Pyropine. 



intensity of terrestrial magnetism, but their reduction must 

 await more leisure. 



I am aware of the poverty of my remarks, and nothing but 

 the scantiness of recorded observations in the interior of Brazil 

 would have emboldened me to submit them to your readers. 



Gongo Soco Gold Mines, W. J. HENWOOD. 



January 16, 1846. 



LIX. On Pegmine and Pyropine, animal substances allied to 

 Albumen. By Robert D. Thomson, M.D., Lecturer on 

 Practical Chemistry in the University of Glasgow*. 



f I^HIS paper was written for a government report, detailing 

 -■• the results of an extensive series of experiments made 

 on the influence of different kinds of food in feeding cattle 

 during the course of 1845. 



The report was drawn up last year, but has not yet been 

 published. In reference to the reducing powers of the ani- 

 mal system, it is remarked that " there is only one instance 

 with which physiologists are at present acquainted that could 

 be adduced as evidence in favour of any substance being ren- 

 dered more complex in the animal system, viz. the production 

 of fibrine or flesh from curd or caseine. So far as chemical 

 experiments carry us, we are not in a condition to affirm that 

 no fibrine exists in milk ; but it must be admitted that none has 

 as yet been detected. If these be correct, then it would ap- 

 pear to follow that the infant fed on milk must derive its flesh 

 from the curd of that fluid ; and that as curd contains no phos- 

 phorus, while fibrine does, the curd of the milk in order to 

 form muscular fibrine is united to phosphorus in the animal 

 system, and is thus built up instead of being, as is the rule with 

 other substances, reduced to a smaller number of elements. 

 The objection to this view of the subject is, that the experi- 

 ments which have been made on fibrine do not prove that it 

 contains phosphorus. They only show that phosphoric acid 

 can be detected in it even when it is purified in the most care- 

 ful manner suggested by chemical knowledge, and it would 

 therefore be somewhat premature to adopt any such analogy 

 as that which we have been considering." 



In support of the view first suggested by Beccaria and ad- 

 vocated in recent times by Prout, that the animal system 

 merely modifies the substances which it employs as food, and 

 does not produce them from its elements, a series of experi- 

 ments made by the writer four years ago, may be quoted, 

 hitherto unpublished, which demonstrate, that in the ocean, as 



* Communicated by the Author. 



