ORIGINS OF AGAMIC PATTERNS 629 



well as in spermatozoa, the spiral features of pattern and the other spe- 

 cific asymmetries develop secondarily in a definite relation to a primary 

 pattern. In this connection it may be recalled that presence of a longi- 

 tudinal physiological gradient has been demonstrated in the ectoplasm 

 of a considerable number of ciliates by various methods, and at present 

 there is no evidence to indicate that the differentials in the protoplasmic 

 substrate and its activities which constitute these gradients are not the 

 primary axiate pattern. If they are primary, the spirals and asymmetries 

 represent secondary structural expressions and differentiations of the pri- 

 mary pattern in the various species-protoplasms. Whether axiate pattern 

 of the spermatid is based on a gradient pattern is not known, but the 

 apparent determination of the spermatid polar axis by an external differ- 

 ential in many forms and the changes in position of parts of the cell sug- 

 gest that a gradient pattern may be present. 



Whether or not the primary pattern in these unicellular individuals is 

 a gradient, the problem of the nature of the spirals and other asymmetries 

 and their relation to it remains. The possibility suggests itself that many 

 of these features of unicellular pattern may result from, or be expressions 

 of, molecular or micellar structure or aggregation in definite orientation. 

 Researches of recent years with polarized light and X-rays have given 

 evidence of orientation of molecules or particles in cellulose membranes 

 and fibers, various animal fibrillar structures, connective tissue, muscle, 

 nerve, keratin of hairs and feathers, chitin, etc. Thus far this evidence 

 of molecular pattern in morphological structure concerns chiefly highly 

 differentiated and structurized protoplasms, proteins, keratin, cellulose, 

 and other nonliving products of protoplasmic activity rather than proto- 

 plasms in general. Various fibrillar structures appear in protoplasms un- 

 der various conditions, but many of these are temporary and disappear 

 completely when conditions change. Granting that proteins, cellulose, 

 and other organic substances are, or may become, indefinitely long chains 

 of chemical groups with definite polarity and symmetry or asymmetry, 

 that these chains may aggregate with definite orientation into larger units 

 (crystallites) which give evidence of crystalline structure, and that these 

 crystallites may also undergo further aggregation with definite orienta- 

 tion, there is, at present, no evidence that a definite and persistent struc- 

 ture of this kind is a primary and fundamental property of protoplasms. 

 It appears rather to be a feature of differentiation and structurization. 

 If this is the case, the definite orientation of molecules or chains is prob- 

 ably not autonomous but a reaction to something; and since these orienta- 



