26 DEFENSIVE FERMENTS OF THE ANIMAL ORGANISM 



correspond to one hundred and twenty isomeric com- 

 binations. We give below the number of possible 

 compounds which result from simply altering the 

 sequence, the form of combination remaining the 

 same. 



The number of Number of resulting compounds, the 



different units sequence only being changed 



8 40,320 



10 3,628,800 



12 479,001,600 



15 ... 1,307,674,368,000 



18 ... 6,402,373,705,728,000 



20 2,432,902,008,176,640,000 



This enormous number of different compounds 

 is solely produced by the manner in which the twenty 



elements follow one another. If hydrolysed. all these 



j j 



compounds would give the same elements to the 

 same amount. These reflections may serve as :i 

 warning to those investigators who are inclined to 

 infer the identity of particular compounds from the 

 presence of the same elements. 



Nor is it only the sequence of the individual units 

 that needs to differ ; for the mode of combination of 

 the different compounds may also vary. The number 

 of possible combinations is infinite. Again, the 

 units are present in unequal quantities. Finally, 

 one very important factor must be allowed for. 

 No cell is composed of only one albumen particle, 

 one carbohydrate, and one fatty substance ; on the 



