28 THE ALBUMINS. 



or less markedly basic. The acid character is most pronounced in 

 the mucins, the nucleo-albumins, and the nucleoproteids ; less so in 

 the globulins ; while the albumins proper are apparently neutral 

 or slightly alkaline. The histons and the protamins, on the other 

 hand, are markedly basic. 



Solubility. Some albumins are soluble in water, others only in 

 dilute saline solution, and still others in dilute acids and alkalies. 

 In more concentrated acids and alkalies, as also in glacial acetic 

 acid, all albumins dissolve, but are at the same time decomposed. 

 In dilute alcohol some albumins dissolve with comparative ease, 

 but in absolute alcohol, ether, chloroform, benzol, and all other 

 common solvents they are insoluble. 



Crystallization. In the eggs of certain fishes and amphibia so- 

 called yolk platelets may be observed which apparently possess a 

 crystalline structure. Chemical examination has shown, however, 

 that these bodies are not pure albumins, but that they contain a 

 large percentage of lecithin and mineral salts. The same is true 

 of the aleuronat crystal which have been found in the seeds of cer- 

 tain plants, and probably also of the eosinophilic crystalloids which 

 may be seen in the blood of birds, of similar structures in the ova 

 of the deer, and the testicular epithelium of man. 



The form in which the albumins are commonly obtained in the 

 chemical laboratory, and in which (with the exceptions mentioned) 

 they exist in nature, is amorphous. In the dry state they form a 

 white or but little colored non-hygroscopic powder, or they occur 

 as yellowish, brittle, more or less opaque lamella which are both 

 odorless and tasteless. 



By artificial means it is possible to obtain certain members of the 

 group in crystalline form. To this end, a neutral Halt must be present, 

 and it is advantageous to have the reaction slightly acid. What 

 part the salt and the acid play is not known, but there is evidence 

 to show that either the acid or the salt enters into the composition 

 of the crystals. In the case of edestin Osborne has shown that a 

 salt-like body results, which contains hydrochloric acid when crys- 

 tallization has taken place from a solution of the albumin in sodium 

 chloride, or sulphuric acid if a sulphate has been employed. 



Of animal albumins, crystallization has been effected in the case 

 of serum-albumin (from horses' blood), egg-albumin, oxyhaemoglobin, 

 haemoglobin, methsemoglobin, and possibly also of lactalbumin and 

 casein. Artificial crystallization of animal globulins has not led to 

 satisfactory results ; but, one substance which supposedly belongs to 

 this class, and which was noted by Noel Paton in a pathological 

 urine, separated out spontaneously in crystalline form. 



Of vegetable albumins, the edestins (globulins) are notable ex- 

 amples of crystallizable albumins, but in their case also the presence 

 of a salt is necessary. This can subsequently not be removed with- 

 out impairment of the power of crystallization. 



The form of the crystals seems to vary ; but Wichmann has 



