CHAPTER VII 



ENDOCRINE ARITHMETIC 



HOW much of a given hormone is found in the body 

 at one time? How much is produced in a day? How 

 much is found in the gland at one time ? What is the 

 output of a single cell? These are questions to which we must 

 have an answer if we want to understand the glands of internal 

 secretion and use our knowledge for the benefit of mankind. 

 Certainly every merchant must have this kind of information 

 about his stock in trade, and the manufacturer about his 

 materials and his product. The science of endocrinology is, 

 however, a long way from any such basis for calculation. 

 How can we measure the output of a factory (i.e. an endocrine 

 gland) when we do not know exactly what raw materials it 

 uses, how it makes the product, or what becomes of the prod- 

 uct when it is used? In the case of most of these chemical 

 factories we do not even know the capacity of the manufac- 

 turing plant. The insulin factory, for example, consists of 

 many thousand bits of tissue, the pancreatic islets, irregular 

 in size and shape, scattered through the pancreas. In the 

 pituitary, although the gland is measurable as a whole, we do 

 not know what particular cells are associated with the various 

 hormones made in the gland, nor even indeed just how many 

 hormones it produces. So it goes throughout this puzzling 

 system of glands. We are dealing at present largely with 

 unmeasurable organs and with incalculable processes. We are 

 able only to appreciate some of the end results, not the funda- 

 mental steps. To measure and calculate what is going on 

 within the glands and thus to understand the chemical reac- 

 tions and strike the balance of input and outgo — that task 

 lies ahead. 



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