FUNCTIONAL SIGNIFICANCE MITOCHONDRIA 443 



Kossel's theory of the nature of the protein molecule, which 

 attracted world wide notice because of the psychological factor 

 involved in the supposed manufacture of living substance. 



It is impossible to predict whither this mitochondrial work 

 will lead us in pathology, certainly, however, toward a truer 

 appreciation of the importance of the behavior of protoplasm 

 in pathological conditions, because now we have a cytoplasmic 

 criterion of cell activity as well as a nuclear one.^^ 



It has already proved fruitful in connection with our con- 

 ceptions of cell structure, for it has enabled us to advance one 

 step further than Schultze did when he defined protoplasm as 

 being a glass-like, semifluid material in which granules are 

 embedded. We can now recognize, with precision, among his 

 granules one great class, the mitochondria, which are more or 

 less distinct chemically and morphologically and which we have 

 good reason to believe occur in almost all protoplasm. The 

 movements of mitochondria in living cells tend to confirm our 

 deeply rooted mistrust of the ancient doctrine of a cytoplasmic 

 reticulum, which, as I have already said persists in the form of 

 misleading diagrams in even our most modern text books of 

 histology. Moreover, this line of investigation has placed us 

 in a position where we can consider in a new light certain con- 

 ceptions of the constitution of protoplasm, Altmann's 'bioblast' 

 and Flemming's 'filar' theories in particular, for we recognize 

 in some of the 'bioblasts' and in some of the 'fila' our mitochon- 

 dria. We appreciate their superficiality and we realize as never 

 before that we will have to look far deeper for clues as to the 

 nature of that mj^sterious and remarkable organization in 

 living matter of which the phenomena of polarity and bilaterality 

 are the visible expressions. 



" ^'cry recently Goetsch has demonstrated, in a paper publislied in tlie May 

 nuinl)er of the Johns Hopkins Hospital Bulletin, that an increase in mitochon- 

 dria is associated with an increase in the activity of the thyroid epithelium and 

 with the severity of the clinical symptoms of hyperthyroidism. 



