42 The Significance of Chemical Molecules 



Protein bodies are indeed products of life, but not the 

 bearers thereof; they do not offer us, in the chemical 

 laboratory, any essentially different quantities than the 

 other more complicated compounds. Protoplasm, how- 

 ever, is the bearer of life; it is distinguished from all 

 chemical substances by its power of assimilation and of 

 reproduction. The nature of these two processes will 

 undoubtedly be recognized some day, but up to the pres- 

 ent time they are still in complete darkness, and even 

 the boldest minds have not yet succeeded in lifting even 

 as much as a corner of the veil that covers them. 



The designation of protoplasm as a protein body, or 

 as a mixture of such bodies, is based upon chemical analy- 

 ses and micro-chemical reactions. The latter undoubt- 

 edly betray the quite common presence of protein in pro- 

 toplasm. But the explanation of this fact is obvious. 

 Protein can very well be dissolved in the water of imbi- 

 bition of protoplasm, since it can be proven to occur fre- 

 quently in solution in the cell-sap. It is even not 

 improbable that, in killing the protoplasts, protein bodies 

 are frequently formed. But, in order to be able to assert 

 that protoplasm and protein are identical, it ought at least 

 to be demonstrated that protein-reactions are lacking 

 neither in any protoplasm nor in any individual organ 

 thereof. But such does not, by any means, appear to be 

 the case.'^ Nucleus, trophoplast, and nucleo-plasm, have, 

 it is true, never been observed without protein, in well 

 nourished cells ; but, whether the wall of the vacuoles and 

 the plasma-membrane are structures that contain protein, 

 is still very questionable.^ 



Chemical analyses have, without doubt, brought to 



7Cf. Zacharia.s. E. Bot. Zcit. 4: 209. 1883. 

 8Cf. Jahrh. IViss. Bot. 14: 512. 1883. 



