c 



40 Vitality and Organization of Protoplasm. 



activity, and yet withal remain identical. The living substance is in 

 this sepse the only substance we have, or can have, any knowledge of. 



Protoplasm is often looked upon as a mere mixture of various organic 

 substances, which in combination, or singly, are believed to "be the bear- 

 ers of vital properties. But no kind of statical substance can be alive, 

 or be the bearer of vital properties. Life consists essentially in the ever 

 sustained chemical and dynamical^play of the _organigni_with its ,me- 

 dium. In a publication of 1882 I said:* "As regards the chemical 

 composition of the living substance, how could it ever be possible to 

 ascertain the same? No analysis of such a synthetic unity, of a sub- 

 stance that is throughout in constant chemical flux, can throw any light^ 

 on vital motility, which is the immediate mass-manirestation of the in- 

 divisible, self-rounded play between the continually reintegrated proto- 

 "plasm, and its as continual disintegration by the influences of the 

 medium." Recently Johannes Reinke, who has assiduously labored to 

 ascertain the chemical constitution of protoplasm, has emphatically ar- 

 rived at the same conclusion. He says : "Dead protoplasm is no longer 

 real protoplasm, just as little as a watch ground, to powder continues to 

 be a watch." He, therefore, likewise looks upon the protoplasmic in- 

 dividual as an indiscerptibly organized whole, whose structure he there- 

 with holds to be the "dominant" agency in functional activity. 



By close observation of visil)le occurrences we have. I think, succeeded 

 in gaining some positive, not merely h5^pothetical, insight into the real 

 nature of the living substance, and of that which constitutes its vitality; 

 an insight far more profound and instructive tlian any aggregational 

 theory has ever afforded. We have discovered the ways and means by 

 which the peculiar chemical substance, called protoplasm, comes to be 

 alive; and have found that it is a living substance only by dint of the 

 cycle of chemical activities by which it is constituted and maintained 

 during its interaction with the medium. 



ASSIMILATION. 



The fundamental process of alternate disintegration and reintegra- 

 tion, which gives rise to vital motility, involves, as indispensable ad- 

 juncts, nutrition and depuration. On the one hand it necessitates ap- 

 propriation, preparation and assimilation of complemental material fit 

 for recomposition ; on the other hand oxydation and elimination of 

 waste products of decomposition. 



Food serves essentially as restitutive material, and not as is often 

 asserted, as fuel which is supplying from outside by force of its oxyda- 

 tion the moving energy, which sets an otherwise immobile machinery 

 going. In 1870 (Centralblate fur die Med. Wiss. Xo. 11), the present 

 writer published ohservations on the living muscles of locusts, which 

 induced him to conclude, in opposition to tlie generally accepted views 

 of Julius Robert Mayer, that the contraction of muscular fibres is not 



■'Menaiselio Zeilsclirift fiir Xiitui\\ iszonsphafl. vol. X^■|l^. ]i. 080. 



