ORIGINS OF AGAMIC PATTERNS 631 



even those of rather closely related forms; and radially symmetrical cili- 

 ates apparently succeed in life as well as the extreme asymmetrical forms. 

 It often appears as if the individual makes the best of the pattern it 

 possesses. 



If the morphological asymmetries of these forms are expressions or 

 results of molecular orientations and aggregations, we still know nothing 

 about the relation between a particular morphological asymmetry and 

 a particular pattern of molecular character. It seems highly improbable, 

 however, that molecular or supermolecular patterns develop independ- 

 ently of the activities and conditions in the metabolizing protoplasm in 

 which they originate. In so far as they may be features of the morpho- 

 logical patterns of spermatozoa, protozoa, or other forms, they are evi- 

 dently localized and integrated in an orderly manner in relation to some 

 more general pattern, so that an individual with definite, species-specific 

 asymmetries results. That the ordering and integrating factors must in- 

 volve a spatial metabolic pattern seems beyond question, and the most 

 general evidences of such pattern are the gradients. Moreover, experi- 

 ment has shown so generally that these patterns do not arise autono- 

 mously in the cell or cell mass concerned but are induced by, or related 

 in a definite manner to, parental pattern or to some factor in intra- or 

 extraorganismic environment that it may at least be questioned whether 

 organismic patterns ever do originate autonomously. 



PATTERNS OF CERTAIN CELL WALLS AND SURFACES 



Work with the ultramicroscope and the polarizing microscrope and 

 X-ray analysis have led to the conclusion that cellulose consists of molecu- 

 lar chains of variable length. A parallel orientation of these to form a 

 definite pattern has been found in the cellulose layers of many plant cell 

 walls and in plant fibers. Microscopically visible striae in cellulose layers 

 of certain cell walls correspond closely with the pattern indicated by 

 X-ray analysis and are regarded as resulting from aggregation of the paral- 

 lel chains. 



The cell wall of the alga Valonia is an interesting example. The Valonia 

 thallus is primarily a single multinucleate, more or less spheroidal, or 

 somewhat elongated cell, often attaining a length of several centimeters. 

 A layer of protoplasm adjoins the wall, and inside this is the large vacuole. 

 The cell wall consists of many cellulose layers, each of which shows 

 microscopic striations in a certain direction. Polarization and X-ray stud- 

 ies of this wall indicate that each layer consists of cellulose chains in 



