Intramolecular reactions of the functional groups scattered onto a polymer chain were discussed in connection with the possibility for controlling the reaction. At first, experimental results in the reactions between two functional groups of X-Y type molecules were presented. The chain length dependence of intramolecular reaction was discussed in reference to the ring-closure probability of the polymer chain. Several ways for calculating the probability were described. In the latter part, the intrachain reaction of polymers containing randomly spaced reactive groups (substrates) and catalytic groups, was described. Kinetic theories considering the distribution of the catalytic groups on the chain, were derived and applied to several experimental results.
Phase separation phenomena of polyelectrolyte solutions were reviewed. The follwing three systems were discussed; 1) liquid-liquid phase separation of water-polyelectrolyte-neutral salt systems, 2) water-polyelectrolyte systems with addition of divalent counter ions, and 3) complex coacervation of polycation and polyanion. For the system 1), a brief account of phase diagrams and plait points, especially their molecular weight dependence, was presented. The system is important not only for molecular weight fractionation but also to determine the Theta point of polyelectrolyte salt solutions. The precipitation or gelation phenomena of the system 2) were explained by specific site binding of counter ions on polyian WhiCh eventually leads to three dimensional network formation, thus, precipitation ar gelation. Recent experimental research of the complex coacervation were reviewed, and the comparison between the Voorn-Overbeek theory and the phase diagrams leads to the conclusion that electrostatic free energy term is not sufficient to cause phase separation, but heat therm must be also taken into account.
1. Photosensory transduction in aneural systems was exemplified by non-flagellar propulsive gliding of trichomes of cyanophytes and by movements of Euglena induced by flagellar activity. The intracellular transduction mechanism of the latter was schematized by modifying the Diehn's model10) (Fig. 1). 2. Dermal photosensitivity is involved in various types of on- and off-reflexes and of tactic and kinetic movements. In a number of animals, dermal and ocellar photoreception often co-exists and the work of Gwilliam37) on Nereis was considered to be a good example (Fig. 2 ). 3. Neuronal photosensitivity functions in inducing reflex movements (crayfish and sea-urchins, Fig. 3), in entraining the circadian rhythm in locomotor and some nervous activities (Aplysia) and in facilitating the conduction of excitation evoked by tactile stimuli (Onchidium). The work of Brown and Brown59) on the giant neurone of Aplysia was discussed in relation to the Ca++ theory on the photoexcitation mechanism. 4. Differentiation of photoreceptive organs may be correlated to development of mass potentials (ERG) at on and off. Poorly organized ocelli produce no detectable ERG. When more differentiated, ERG's consisting of multiple components appear at on (Fig. 4). The sustaining level in ERG's during illumination as seen in higher animals seems to require a more elaborate organization of the receptive layer (Fig. 5). 5. Differentiation of photosensory cells is manifest as enlargement of the photoreceptive surface which is achieved at first by utilization of ciliary shafts and then by formation of microvilli. A change over from motile to non-motile cilium appears to be associated with the first step of elaboration as a photosensory cell. A tentative scheme relating morphologically dermal, neuronal and ocellar photoreceptions was presented. (Fig. 7).