322 SECTIONAL TRANSACTIONS— B. 



polysaccharide configuration. It is an interesting point that the chief 

 longitudinal spacings of muscle and unstretched hair are almost equal to 

 the length of a glucose residue as it is known in cellulose ; while the fact 

 that the crossed cellulose chains of the wall of Valonia ventricosa are laid 

 down according to a definite plan indicates that they are formed on a net- 

 work pattern in the underlying protoplasmic layer. 



Saturday, September 3. 



Visit to works of Imperial Chemical Industries (Fertilisers and 

 Synthetic Products) Ltd., Billingham. 



Sunday, September 4. 



Excursion to Kirkham Abbey. 



Monday, September 5. 



Discussion on Water pollution [survey of the River Tees) (Dr. H. T. 

 Calvert; Mr. J. Longwell; Dr. R. W, Butcher and 

 Mr. F. T. K. Pentelow; Dr. B. A. Southgate; Mr. W. B. 

 Alexander ; Mr. R. Bassindale) : — 



Dr. H. T. Calvert. — The purpose and nature of the survey of the 

 River Tees. 



Mr. J. Longwell. — The decomposition of sewage in river water. 



The self-purification of the upper reaches of the river Tees has been 

 studied from the results of chemical analysis combined with measurements 

 of the flow of the river— that is, from determinations of the actual quantities 

 of the polluting constituents. Rate of self -purification from sewage pollu- 

 tion appears to be dependent mainly on temperature. Thus, below Croft, 

 where the Tees receives sewage pollution from the Skerne, a much greater 

 distance is required in the winter than in the summer for the same amount 

 of purification. 



Dr. R. W. Butcher and Mr. F. T. K. Pentelom^.— T^e effects of 

 pollution on the biology of the non-tidal reaches of the River Tees. 



The biological work in the upper reaches of the Tees has dealt primarily 

 with ' sewage fungus,' the algae and the macroscopic fauna. Above Croft 

 the river is relatively pure, except for short distances below two sewage 

 outfalls. At Croft the Skerne joins the Tees and carries a considerable 

 quantity of sewage. The area occupied by sewage fungus varies with 

 changes in the chemical composition of the water. Large quantities of 

 the filamentous alga, Cladophora glomerata, occur in May and June from 

 Croft down to the tidal reaches, but only small quantities grow just below 

 the two sewage outfalls above Croft. The distribution of some other algae 

 appears also to be affected by pollution. The flora, microscopic and 

 macroscopic, is much richer below than above the Skerne. Sewage pollu- 

 tion also has a marked effect on the fauna, water-snails, leeches and Asellus 



