174 LIFE AND DEATH. 



stituent cells it is the exclusive substance of Primus; 

 and, in the same way, the living matter of another 

 individual Secundus will carry everywhere his per- 

 sonal impress, which differs from that of Primus. 



But it is none the less true that this absolute 

 specificity is based with certainty only on differences 

 which from the chemical point of view are exceedingly 

 slight. All these protoplasms have a very analogous 

 composition. And, if we regard as negligible the 

 smallest individual, specific, generic, or ordinal varia- 

 tions we may then speak in a general manner of 

 protoplasm or living matter. 



Experiment shows us, in fact, that the real living 

 substance — apart from the products it manufactures 

 and can retain or reject — is in every cell tolerably 

 similar to itself The fundamental chemical re- 

 semblance of all protoplasms is certain, and thus 

 we may speak of their typical composition. We 

 may sum up the work of physiological chemistry for 

 the last three quarters of a century by affirming that 

 it has established the chemical unity of all living 

 beings — that is to say, a very notable analogy in the 

 composition of their protoplasm. 



This living matter is essentially a mixture of the 

 proteid or albuminoid substances, to which may be 

 added other categories of immediate principles, such 

 as carbohydrates and fatty matters. But the latter 

 are of secondary importance. The essential element 

 is the proteid substance. The most skilful chemists 

 have tried for more than half a century to discover 

 its composition. Only during the last few years 

 — thanks to the researches of Kossel, the German 

 chemist, following on those of Schultzenberger and 

 Miescher — we are beginning to know the outer walls 



