PEOTOPLASM 1 1 



solution, and by being precipitated from solution by half 

 saturating with ammonium sulphate. 



2. Proteoses (Proteins with a less complex molecule than 

 albumins and globulins). They may be formed from albumins 

 (albumoses) and globulins (globuloses), by the action of super- 

 heated steam and during digestion. Under the influence of 

 these agents, the complex molecule splits into simpler molecules 

 and takes up water. 



These proteoses form a series between the original proteins 

 on the one hand, and the peptones or simplest proteins on the 

 other. They may be divided into two classes : 



(a) Those nearly allied to the original proteins Proto- 

 proteoses, which are precipitated in a saturated solution of 

 sodium chloride, NaCl. 



(6) Those more nearly allied to the peptones Deutero- 

 ppoteoses, which are not precipitated in a saturated solution 

 of NaCl, but are precipitated by a saturated solution of 

 ammonium sulphate. 



3. Peptones. These are products of the further splitting of 

 proteoses. Their characteristic reaction is their solubility in 

 hot saturated ammonium sulphate solution. They diffuse very 

 readily through an animal membrane. 



(B) Conjugated Proteins 



Proteins have a great tendency to link with other sub- 

 stances, and the following compounds are thus produced : 



(1) Proteates (Meta-proteins) are formed by linking acids 

 or alkalies to the native proteins. 



(2) Nueleins, so called because their existence was first 

 demonstrated in the nuclei or central parts of the cells of the 

 body, may readily be split into a protein part and into nucleic 

 acid, a phosphorus-containing material of definite composition, 

 having an acid reaction, and containing about 10 per cent, of 

 phosphorus. In certain places the amount of nucleic acid is 

 large in proportion to the protein, in others it is small. The 

 term nuclein is usually confined to the former, nucleo-albumin 

 to the latter of these. From the pure nucleic acid, which 

 occurs along with protamine in the heads of spermatozoa, to the 

 proteins almost free of phosphorus there is a continuous series. 



