SECTIONAL TRANSACTIONS.— I. 599 



circulating protein, which was metabolised by the cells relatively easily as compared 

 to the more stable tissue protein ; (2) Pfluger's theorj', on the other hand, held that 

 all ingested protein became an integral part of the living cell before it was metabolised. 

 The experiments planned on the superimposition method, and both the nitrogen and 

 the sulphur in the intake and output being estimated, show that when equilibrium is 

 attained the body excretes qualitatively the same material as is ingested. During, 

 however, the three days when the nitrogen output is rising to the new level, the 

 material retained is found to be relatively sulphur poor. Correspondingly when the 

 nitrogen output falls the material lost is relatively sulphur poor. The evidence seems 

 to show that at any time the material in transit is poor in sulphur and does not 

 correspond qualitatively to muscle tissue, as is the case when there is a definite building 

 up of tissue. This is in agreement with the evidence that the sulphur moietj' of the 

 protein molecule is more quickly metabolised than that of the nitrogen. 



Dr. W. A.. Burnett. — Chronaxie. 



Discussion on Cell Structures. (Prof. J. Bronte Gatenby ; Dr. Rogers 



Brambell.) 



Dr. Rogers Brambell.— The terms ' Golgi Apparatus ' and ' Golgi Bodies ' 

 should be confined to those cell structures which can be shown to be homologous 

 to the internal reticular apparatus of the neurone. Such structures are found in 

 all animal cells properly examined. The relation of the Golgi apparatus to vacuoles 

 and other cell structures is discussed, with special reference to the ' vacuome ' theory 

 of Parat. The function of the Golgi apparatus in cell metabolism is obscure, but it 

 appears to be a centre of formation of yolk and secretion, and probably is concerned 

 with the formation of the Nissel substance in the neurone, as well as with the formation 

 of the acrosome in spermatogenesis. Artefacts produced in colloidal emulsions 

 supply evidence concerning the chemical composition and physical state of the Golgi 

 apparatus in the living cell. 



Friday, September 7. 



Joint Discussion with Section M on Lactation and Nutritional Factors 

 allied thereto. (Dr. H. E. Magee ; Prof. E. P. Cathcart, C.B.E,, 

 F.R.S. ; Capt. J. Golding ; Dr. N. C. Wright.) 



Dr. H. E. Maoee. — It has been abundantly shown that at the height of lactation, 

 heavy milking animals habitually lose more calcium and sometimes more phosphorus 

 from their bodies than they can assimilate. This loss of calcium, if continued through 

 repeated lactations without adequate recuperative periods, eventually ends in failure 

 of breeding capacity, a result which is accelerated by diets poor in calcium. Attempts 

 to make good the loss of calcium by feeding large amounts of it in soluble or insoluble 

 form have proved only partial!}' effective. Recent work has shown that ultra-violet 

 light and cod-liver oil lead to a greatly increased retention of calcium and sometimes 

 of phosphorus at all stages of lactation by diminishing the isecal excretion of these 

 elements. 



Prof. E. P. Cathcart, C.B.E. , F.R.S. — I think the marvellous phenomena 

 involved in mammary gland activity are lost sight of in the emphasis laid on the 

 economic aspect of milk production. Far be it from me to stress the apparently 

 academic versus the economic aspect of the problem. I am alive to the importance 

 of the economic side, but if advance is to take place the purely research side must 

 not be neglected. 



After all, what do we reallj' know about the secretion of milk, about the formation 

 of its characteristic constituents, of this gland which keeps its secretion so approxi- 

 mately constant in percentage composition ? It may be true that selective breeding 

 has increased the total yield, but it has done but little to influence the composition. 

 As regards the exact mode of formation of the protein carbohydrate and fat, I think 

 it can be said definitely we know nothing. To me it is a true matter for wonder. A 

 gland which only functions under, it is triie, a physiological but very specific stimulus 

 — what can be said definitely and unequivocally of the actual nature and source of 

 origin of the stimulating substance ? 



