212 PHARMACEUTICAL BACTERIOLOGY y 



3. General. From the above it has no doubt become evident that 

 the subject is far from clear nevertheless we may submit certain propo- 

 sitions as being more or less conclusive and which will serve to elucidate 

 some of the more or less problematical statements which follow. 



a. As far as is known, all substances which may be designated as 

 ferments, are formed by living plasm within living cells. Ferments may 

 be developed in single-celled plants and animals and in tissues and organs 

 of higher plants and animals. 



There is some dispute whether or not enzymes came into existence 

 prior to living matter. Troland and others assert that certain autocata- 

 lytic enzymes or protoenzymes came into existence spontaneously in the 

 remote geologic periods and that these greatly increased the chemical 

 changes so essential to the creation of living plasm. There is no way of 

 either proving or disproving the idea and it is a fact that all growth activi- 

 ties manifest the characteristics of enzymatic influence. 



b. Since no ferments have as yet been isolated in purity, nothing is 

 known regarding their exact physical and chemical characters and prop- 

 ^erties. It is, however, generally conceded tSaTjthey are organic, of an 

 albuminoid nature, and chemically quite complex.. 



c. Ferments, under favorable conditions, are capable of inducing 

 chemical changes in organic substances, resulting in new compounds which 

 are always simpler in composition than the mother substance. In induc- 

 ing these changes the ferment itself does not undergo decomposition. 



d. To distinguish between organized and 'unorganized ferments is no 

 longer tenable. All ferments, as far as is known, are organized in so far as 

 they are of living origin. 



e. Ferments and the end products of their activities are immediately 

 independent of the vital processes of the cells that produce the ferments. 

 The ferment or enzyme of yeast (zymase), for example, is not necessary 

 to the maintenance of the protoplasmic activity of the yeast fermenta- 

 tion, as alcohol and carbonic acid gas, as they are not used in the metabolic 

 processes of the yeast cell. Nevertheless, the ferments or enzymes appear 

 to be essential to the life of the enzyme forming organisms. 



f. Ferments are chemically unstable. They are checked in their 

 activity by low temperatures (10 to o C.) and killed by high tempera- 

 tures (45 to 70 C.). 



g. Ferments are only slightly dialyzable, but most of them will pass 

 through porous niters (filter paper, porous clay, etc.), under pressure. 



h. Ferments are precipitated by alcohol, though not completely. 

 They are precipitated in proportion to the percentage strength of the 

 alcohol. They are soluble in water, in aqueous solutions of glycerin, in 

 weak acids and alkalies, and in neutral salt solutions. In a general way, 



