VIRUS PROTEINS — STANLEY 507 



on Tuesday. You all know how readily you can induce crystalliza- 

 tion of substances by merely introducing a tiny crystal of the material 

 into a saturated solution. The atoms come out of the solution and 

 line up in a fashion that is predetermined by the pattern presented 

 in the form of the introduced crystal. In some of the complex silicates 

 such as Na^FcjAluBsSi^Osg you may have from five to ten different 

 components present in the solution and yet they all arrange themselves 

 according to the pattern that is presented to them. In some instances, 

 this tendency to assume a definite arrangement is so strong that 

 apparently it may occur without the addition of the pattern or crystal 

 seed. In other instances, the arrangement or crystallization will not 

 occur without the pattern first being present. Well do I remember 

 the time at school when a certain compound was synthesized for the 

 first time in this country. Despite repeated attempts under all kinds 

 of conditions, the material could not be caused to crystallize. How- 

 ever, when a small amount of the material in crystalline form, which 

 had been obtained from abroad, was added, the compound synthesized 

 in this country crystallized quite readily, and since then it has been 

 possible to crystallize the material without knowingly adding seed 

 crystals. We say that the laboratory has become "seeded," that 

 small amounts of such crystals probably occur throughout the 

 laboratory. Here, therefore, we have an example of an arrangement 

 that was dependent upon the presence of a pattern and a demonstra- 

 tion that chemically undetectable amounts of material are probably 

 sufficient to serve as a pattern. The forces responsible for this 

 orientation may appear mysterious, yet they are definite and specific 

 and they are real. 



Now, let us consider first what may happen on the introduction of 

 a virus protein molecule into a certain cell, and then consider whether 

 or not we may interpret the growth of protoplasm in terms of this 

 happening. It seems likely that in a living cell there exists a vast 

 array of compounds ranging perhaps from salts and simple amino 

 acids, through intermediate compounds such as carbohydrates and 

 polypeptides, to complex compounds such as proteins. Consider 

 whether the virus protein molecule is able through a characteristic 

 structure and the surface forces that I have described to cause all the 

 component parts to come from this storehouse of materials and to line 

 up in orderly fashion alongside the pattern. If we may assume this 

 degree of orientation, then I think we may assume that, inasmuch as 

 the intact virus protein molecule represents a more stable form, there 

 will be a mutual solvation of forces with the formation of the intact 

 molecule which is then freed from its original pattern and ready to 

 begin its own cycle. I have pictured this happening in a rather naive 

 manner for the sake of simplification. Actually, the synthesis of pro- 

 teins probably results from a series of interrelated chemical reactions 



