16 Dr. Golding Bird's Experimental Researches 



animal fluids in which its presence was unsuspected, and thus 

 bring us acquainted with some new combinations of this im- 

 portant product of organization : this remark has certainly 

 received some support from the facts that have fallen under 

 my notice during the last three years, and which I propose to 

 detail in this paper. In the last number of the Guy's Hospitalre- 

 ports, I have related such of my experiments as appeared to be 

 connected with the physiological bearings of this subject, I shall 

 therefore confine myself in this communication to the strictly 

 chemical investigations, in the hope that they will assist in re- 

 moving the obscurity hanging over that part of animal chemis- 

 try connected with the peculiar and ill-defined organic princi- 

 ples existing in mucus, saliva, &c., and stated by most chemical 

 writers to differ from albumen in their chemical characters. 



1. Mr. Brande, in a paper published in the Philosophical 

 Transactions for 1809, first demonstrated the existence of al- 

 bumen in saliva and mucus, and it is a matter of regret that 

 this philosopher has not followed up these views, as much light 

 must have been thrown on this subject by researches guided 

 by his talent. The state of combination in which the albumen 

 existed in mucous fluids Mr. Brande failed to discover, 

 although he remarked that in some features it resembled very 

 closely an alkaline albuminate. Before giving an account of 

 the results obtained by a repetition of his interesting experi- 

 ments, it will be proper to describe the behaviour of those se- 

 cretions, in which the presence of albumen was suspected, 

 towards re-agents, as it will serve to bring us acquainted with 

 a combination of albumen, differing from any described in my 

 previous papers. For this purpose, saliva, or any other mucous 

 fluid which does not coagulate by heat, may be taken as an 

 example, and perhaps that viscid glairy fluid secreted during 

 the first few days of acute bronchitis is the best for our pur- 

 pose, as from its abundant secretion, and the frequency of the 

 disease, it can be obtained in sufficient quantity for satisfactory 

 chemical investigation. This form of mucus appears at first 

 to be rather opake, from the presence of innumerable air- 

 bubbles, but by repose in a cylindrical vessel these rise to the 

 surface, and a nearly limpid fluid is obtained : this does not 

 coagulate by heat, and presents the following appearances 

 with re-agents : — 



A. On the addition of sulphuric acid a reddish-brown so- 

 lution is formed ; which by dilution with water loses its colour, 

 and becomes quite transparent. 



B. Nitric acid appears atjirst to coagulate it^ rendering it 

 yellow in patches, and by the assistance of heat forms a pale 

 yellow solution, becoming brown on the addition of an alkali. 



