TJJE OUTLOOK 599 



of rubber and of the gums and mucilages, the adhesive quality of gela- 

 tin, the glaze communicated to surfaces by colloids in general and starch 

 and dextrins in particular, and the hard surfaces communicated by the 

 drying oils are already utilized in a multitude of ways in our manu- 

 factures and our daily affairs; but the possibilities held out by the 

 products of life are far frcm being exhausted by these few instances. 

 Among the proteins, for example we find elastin, distinguished by its 

 possession of the rare combination of elasticity and tensile strength 

 without rigidity, spongin exhibiting, although in a different way, a 

 similar combination of qualities, keratin, distinguished by its hardness, 

 insolubility, translucency and ability to take a polish, fibroin distin- 

 guished by its extraordinary tensile strength, lightness and insolubility. 

 These few examples suffice to show us what a variety of physical char- 

 acteristics the various proteins may display, and since these substances 

 do not differ profoundly from one another in structure and compo- 

 sition, we may infer that a relatively slight chemical change may confer 

 upon a protein an entirely new series of physical characteristics. An 

 example of this is afforded by the effect of union with formaldehyde 

 upon the physical characteristics of casein. 



The proteins are, at present, sparingly employed in the manufac- 

 tures, but casein is used as a substitute for celluloid, and buttons, 

 hair-combs, billiard-balls, and other objects formerly made of ivory or 

 celluloid are now made of casein rendered horny in consistency by 

 treatment with formaldehyde or calcium hydroxide. Casein is further- 

 more utilized as a vehicle for pigments in paints, as a finishing and 

 water-proofing material, and for the manufacture of non-inflammable 

 moving-picture films. The uses of gelatin are manifold and well- 

 known. The employment of the relatively expensive proteins of animal 

 origin in the manufacturing industries, however, is excessively wasteful 

 and cannot continue indefinitely, or expand to very great dimensions. 

 We must seek substitutes for the proteins already used, and new utilities 

 as well, among derivatives of the relatively inexpensive vegetable 

 proteins. The exigencies of the war have, in fact, already called into 

 being a vegetable glue, and a vegetable substitute for casein undoubt- 

 edly merely awaits the seeker. 



In agriculture, our recent acquisitions of knowledge in the field of 

 growth have already profoundly influenced our practice in the feeding 

 of stock for the market and for breeding purposes. Further advances 

 in^this direction, together with precise knowledge of the time-relations 

 of growth in the various domesticated animals, will ultimately enable 

 us with the utmost precision to define the most economical practice 

 of feeding and the optimal duration of growth for the production of 

 calorific and nitrogenous values. In the growth of perennial crops, 

 also, an exact knowledge of the time-relations of the growth-process 

 will enable us to determine with precision the optimal period of growth 

 which should elapse before cropping. Especially in forestry this knowl- 

 edge will increase the economy of our practice. 



