44 



THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 



fore the activities of cells in the investigation of disease and in the study of patho- 

 logical processes have been gaged almost exclusively by the appearance of their 

 nuclei. Now we have at our disposal another criterion of cell activity and of 

 cell injury, the mitochondria, which we have already found to be of great and 

 surpassing delicacy, and which respond, even before the nucleus, to injurious 

 influences. Furthermore, this indicator is cytoplasmic, and as the cytoplasm is 

 more intimately related to the environment than the nucleus, its study may yield 

 very valuable information. It is an entirely different kind of indicator from the 

 nucleus and we may confidently look to it to disclose facts which would never have 

 been revealed by the study of the nucleus alone. That mitochondria are destined 

 to play an important and conspicuous role in medical research, from now on, is 

 quite apparent from Goetsch's (1916, p. 132) recent work on toxic adenomata of 

 the thyroid gland. It may be said, by way of explanation, that all the work on 

 goiter in time past has been vitiated, at the outset, by the fact that we lack a reli- 

 able criterion for the activity of the gland. It has come to be an embarrassing 

 question to ask one to pick out from a number of thyroids, on the basis of the 

 histological a])i)earance, the one which was associated with the clinical symptoms 

 of hyperthyroidism. The height of the epithelium, the appearance of the nuclei, 

 and the amount of colloid are, at best, but poor aids in the dilenmia. Now Goetsch 

 has discovered that, in the cases which he has observed, the mitochondria are 

 enormously increased in number where there are symptoms of hyperthyroidism. 

 In other words, he has succeeded in correlating the perplexing clinical sj^mptoms in 

 the little-known condition of exophthalmic goiter, or Basedow's disease, with a 

 definite anatomical change in the gland itself (/. e., in the mitochondria). Many 

 other conditions lend themselves to work along these lines and the outlook is 

 promising. 



Table 1. — The Terminology of Mitochondria. 



