17 



film, their arrangement will be "smectic" (as distin- 

 guished from crystalline) so as to leave irregular open 

 spaces between them. This accounts for the lateral com- 

 pressibility of the film. 



Besides carbon, nitrogen, oxygen, and hydrogen, there 

 are also present in living matter a number of other ele 

 ments in lesser amounts, especially sulphur and phos- 

 phorus. These have not been considered hereinabove be- 

 cause they are not present in sufficient amounts to con- 

 stitute regular structural elements of the protein chem- 

 ical fabric. In a typical protein there is only about one 

 sulphur or phosphorus atom to every hundred nitrogen 

 atoms, whereas in order to constitute regTilar building- 

 units of polypeptide spirals there would have to be about 

 one sulphur or phosphorus atom to every one nitrogen 

 atom. Sulphur seems to be normally present in the 

 cytoplasm, and phosphorus in the nucleus. The experi- 

 ments of F. S. Hammett at Wistar Institute have shown 

 that the rate of cell division depends on the state of 

 oxidation of the sulphur. The presence of phosphorus 

 seems to be necessary for the assimilation of amino acid 

 residues, from which it appears that the phosphorus acts 

 as a catalyst. 



SYNTHETIC LIFE 



One of the most important questions which confronts 

 science today is whether we know enough about the chem- 

 ical structure of living matter to justify us in making 

 serious attempts to produce life synthetically. The au- 

 thorities of today do not consider our attempts in this 

 direction as being worthy of publication, but let it be 

 remembered that the authorities of a hundred years ago 

 also tried to maintain a similar attitude towards organic 

 compounds, until they were abruptly interrupted by 

 "Wohler's synthesis of urea. The prevailing opinion to- 

 day is that the living organism is too complex to be pro- 



