on the Nature and Pt'operttes ofAlhumenf Sfc. 21 



1 2. From all the foregoing experiments we learn, that fluids, 

 as mucus and saliva, which do not give indications of the pr«- 

 sence of albumen in a satisfactory manner by the application 

 of ordinary reagents ( 1 and 6), by exposure to the air (2 and 8) 

 or to an atmosphere of gaseous hydrogen (3, 8) let tall a de- 

 posit in the form of minute particles, which resembles coagu- 

 lated albumen so closely that we are hardly justified in con- 

 sidering them as distinct. The same fluids when traversed 

 by an electric current of low intensity (9, 10) give up, at the 

 surface of the positive electrode, a white substance, which no 

 chemical reagent to which it has been exposed can distinguish 

 from artificially coagulated albumen. The results thus ob- 

 tained by the action of electricity are corroborative of those 

 obtained by Mr. Brande twenty-eight years previously, the 

 only discrepancy that exists depending upon the surface at 

 which the coagulation took place : to this I should beg to pro- 

 pose a similar explanation to that which I have suggested in 

 my former paper with regard to albumen (23). 



1 3. In consequence of the separation of coagulated albtimen? 

 from saliva by an electric current, the existence of the pecidiar 

 animal matter of saliva (ptyalin of Berzelius) might appear 

 questionable, and it appeared probable that it might be some 

 albuminous combination instead of a distinct proximate prin- 

 ciple. To determine this, some ptyaliji was prepared by 

 evaporating some saliva to dryness, digesting the residue in 

 hot alcohol, and then in cold alcohol acidulated with acetic 

 acid. The insoluble residue, which notwithstanding its wash- 

 ing with alcohol was acid, partly dissolved in water, leaving 

 an insoluble substance very closely resembling, if not iden- 

 tical with, coagulated albumen. The watery solution con- 

 tains, according to Berzelius, {Traite^ v. 6.) tolerably pure 

 ptyalin. This solution was placed in two glass cups con- 

 nected by moistened cotton, and exposed by means of platina 

 wires to the action of an electric current from 36 pairs of 

 plates two inches square excited by weak brine : coagulation 

 ensiled at both electrodes^ most freely at the negative side. 

 This coagulated substance could not be distinguished from 

 albumen, hence it appeared probable that the ptyalin of Ber- 

 zelius consisted of some hitherto unknown combination of 

 that principle. 



As it is obvious that no previously known combination of 

 albumen would present all the phaenomena of the (so called) 

 peculiar proximate principles of mucus or saliva with reagents, 

 although its solutions in alkalies and in carbonic acid would 

 present some, it became a most interesting inquiry to seek 

 after and develop the nature of this unknown combination. 



