THE VOLATILE PART OF PLANTS. 99 



brine was saturated by addition of salt in excess. He also 

 precipitated myosin from tbe juice of the tubers by sat- 

 urating it with salt. 



The myosins are precipitated by conversion into alkali- 

 proteids, when their brine-solutions are depriyed of salt 

 by dialysis or when these solutions ai-e kept for some 

 hours at 100° P. {Sidney Martin. ) 



Vegetable Paraglobulin is recently stated to exist in 

 papaw-juice, and in the seeds of lequirity, Aims preca- 

 torius. It is distinguished from myosin by requiring a 

 higher temperature for coagulation from salt-solutions 

 and in not suffering conversion into an insoluble alkali- 

 proteid by dialysis or long heating to 100° P. {Martin.) 



Acid-Proteids are bodies formed from proteids by the 

 prolonged action of acids. They are insoluble in water, 

 alcohol and brines, but easily soluble in dilute acids or 

 alkalies, and are precipitated by neutralizing these solu- 

 tions. The solutions of acid-proteids in acids are not co- 

 agulable by heat. The albumins and globulins are grad- 

 ually converted into acid-proteids by cold, highly dilute 

 acids, and more rapidly by stronger acids and gentle heat. 

 Syntonin is the acid-proteid resulting from solution of 

 muscle-flesh, or myosin, in weak hydrochloric acid, and is 

 thrown down when the solution is neutralized by an 

 alkali, as a white gelatinous substance. Acid-proteids 

 may exist in seeds such as the oat, lupin, pea, bean, etc., 

 which contain so much free acid, or acid salt, that the 

 water extract is strongly acid to test-papers. 



Alkali-Proteids, or Albuminates. — The action of 

 dilute alkali-solutions on most proteids converts them 

 into bodies which, like acid-proteids, are insoluble in 

 water and salt-solutions, but soluble in dilute acids and 

 alkalies, and are thrown down from these solutions by 

 neutralization. Dilute acids do not convert them into 

 acid-proteids. Alkali-proteids are said to exist gener- 

 ally in the young cells of the animal, and may also occur 



