<254? PRIMARY ANIMAL flVir>S* 



Mucus is nega- The properties of mucus are principally negative; It Is not 

 live as to the coagulable bv lieat, nor capable of becoming gelatinized; it 



preceding cha- '. °, • "•, i , • , , , . °," , 



rafters j but pre- »s not precipitable either by the ox) muriate of mercury or by 

 cip. by aq. lith. 1^,^ but it may be deteaed with confiderable minutenefs by 



the aqua lithargyri acetati. 

 "Other tcfts. It appears therefore that the oxymuriate of mercury, tan, 



and theaqna lithargyri acetati are the three moft valuable tefts. 

 The nitro-muriate of tin is a lefs delicate teft of albumen than 

 the oxymuriate of mercury, and is alfo in fome degree affefled 

 by jelly. The nitrate of filver appears to be a very nice teft 

 of albumen, but it is objectionable in confequence of its being 

 decompofed by the muriate of foda, a fait which is fuppofed 

 to exid in moft of the animal fluids. The nitro-muriate of 

 gold is a delicate teft of albumen, but it likewife precipitates 



jelly. 



Order of analy- In the analyfisof a fluid which is fuppofed to contain either 

 ^' albumen, jelly, or mucus, the firft ftep is to obferve the effect 



of the oxymuriate of mercury; if this produce no precipUate, 

 we may be certain that the fluid in queftion contains no albu- 

 men. We muft next employ the infulion of galls, and if this 

 alfo caufe no precipitate, we may conclude that the animal 

 matter held in folution confifts of mucus alone. 



-Rcmarlc, I have before remarked, that the ideas which I have formed 



of the nature of jelly and mucus, and fhe relation which thefe 

 fubflances bear to each other, differ materially from thofe of 

 Mr. Hatchett. It is not indeed without a degree of diffidence 

 that I diffent from fo diftinguiffied a chemift ; but I conceive 

 that I am juftilied bv the experiments related in this elTay. — 

 Mr. Hatcheft, in the valuable paper to which I have already 

 referred, fpeaks of the white of the egg as confifting of pure 

 albumen; but I believe that in this particular he will be found 

 not perfe6lly accurate. 



Animal mucus There is a great refemblance between the mechanical pro- 



refcmbles vsget. perties of animal mucus and vegetable gum, and I found that 

 they ftrongly refcmble each other alfo in their chemical qualities. 

 A folution of gum arable, containing one grain of gum to 200 

 grains of water, was not affected either by the oxymuriate of 

 ' mercury or by tan. With the nitro-muriate of tin and with the 



nitrate of filver there was only a flight degree of opacity, but 

 with the aqua lithargyri acetati there was a denfe precipitate 

 inftantly formed. 



On 



