I 



28 PROTOPLASM AND THE CELL 



bodies containing no phosphorus. According to Miescher this nucleic 

 acid is a definite chemical body with the formula C 09 H 49 N 9 P 3 O 32 , the 

 phosphorus constituting as much as 14 per cent, of the substance. In 

 combination with proteids this acid forms nucleins. The richer these 

 nucleins are in nucleic acid the more acid they are, and the richer in 

 phosphorus, the more important apparently is their biological role. For 

 example: the important chromatin of the nuclei is a strongly acid sub- 

 stance rich in phosphorus; plastine, the basis of the substance of the 

 nucleolus (Reinke), has less; linin, composing the linin network of the 

 nucleus, still less; while in the nucleo-albumin of the cytoplasm the pro- 

 portion of nucleic acid is small, the substance scarcely acid, and the 

 quantity of phosphorus only 1 per cent., or even 0.5 per cent. Lecithin 

 and cholesterin seem to be accessory and are not properly a part of the 

 albuminous molecule (Delage). Biochemists seem to tend toward 

 the supposition that nucleic acid is the basis of the proteid part of pro- 

 toplasm, and the former is assuredly the predominant portion of the 

 protoplasmic particle. 



Chemical analysis yields various formulae for different sorts of proteid. 

 Bunge gives these four as typical, but calls attention to the divergence 

 in the composition of proteid matter studied under the best of conditions. 



FORMULA OF THE PROTEID FROM 



Hen's eggs C^Hg^O^S, 



Horse's hemoglobin C 680 H 1098 N 210 O 241 S 2 



Dog's hemoglobin C 726 H im N 194 O 214 S 3 



Gourd seed (globulin) C 292 H 481 N 90 O 8 3S 2 



From such a list (and it might be extended almost indefinitely) it is 

 obvious that, however much the idea "proteid" may mean, it does not 

 identify any definite substance capable of being represented, as yet at 

 least, by a numerical formula. As already has been noted, this fact may 

 be due in small part to the impossibility of analyzing protein without 

 first changing it materially. It is, however, due in much larger part and 

 more importantly for the theory of biogen to a consideration of a different 

 sort namely, that proteid has no constant composition to be numerically 

 indicated. We are not dealing here solely with mere chemical affinities 

 between chemical elements of certain valencies and invariable reactions, 

 such as those which take place, for example, when sulphuric acid and 

 ethyl alcohol are heated together in a flask, producing ether : 



(C,H 5 )OH + H 2 SO 4 = (C 2 H 5 )SO 4 H + H 2 O 

 (C 2 H 5 )S0 4 H + C 2 H 5 OH = (C 2 H 6 ) 2 + H 2 SO 4 



The changes by which protoplasmic proteid is produced and changed 

 and reproduced and changed again in plants and animals are practically 

 based on this sort of interchange. There is present, however, in metab- 

 olic reactions a complexity which keeps many of the processes and their 

 products from accurate description. It is this unimagined intricacy of 

 chemical reaction and interaction in biogens which allows the occasional 



