136 THE MITOCHONDRIAL CONSTITUENTS OF PROTOPLASM. 



whatsoever. According to Homans, this remarkable association of changes in 

 the B cells with the condition of diabetes is causal, and indeed this would seem 

 to be the most likely interpretation, though possibly they may be simply the result 

 of the condition. In any case the work constitutes a definite contribution to our 

 knowledge of diabetes on the one hand, and of mitochondria and cell physiology on 



the other. 



Goetsch's work on the thyroid (1916, p. 132) is of particular interest. He 

 has studied colloid goiters and lias found that there is an actual correlation between 

 the chnical symptoms and the amount of th>Toid tissue presenting evidence of 

 thyroid activity by the abundance of mitochondria throughout. That is to say, 

 in cases of colloid goiter, without any symptoms of hyperthyroidism, the mito- 

 chondria are generally reduced in number to the point of being almost entirely 

 absent. Those present are smaller than normal and there is a considerable 

 increase in the amount of fat. In the cases of adenoma with hyperthyroidism, the 

 cells of the adenoma are enormously rich in mitochondrial substance in the form 

 of granules and short, thick rods, and contain no fat. In every instance of exoph- 

 thalmic goiter the thyroid gland has been found to contain a great abundance 

 of mitochondria, much in excess of the normal amount and with little or no fat. 

 In fact, the correlation of the chnical manifestations of hyperthyroidism and the 

 mitochondrial picture is such that Goetsch is justified in saying that the two are 

 definitely related. His conclusions are based upon the study of approximately 

 125 cases of thyroid disease in the human. 



BLOOD VASCULAR SYSTEM. 



The blood offers a unique opportunity for the study of mitochondria because 

 they can so well be seen in the living cells by staining with janus green as well as 

 in fixed smears stained by appropriate methods. Nevertheless, investigators have 

 contented themselves with merely describing the mitochondria in the normal cells. 

 Considerable attention has been paid to the mitochondria as possible indicators 

 of the genetic relationship of blood-cells to each other. Blood from cases of anemia 

 and leukemia has been studied simply because it contains- cells which are normally 

 restricted to the bone marrow and which can not be obtained under normal condi- 

 tions without an operation or early autopsy. The question of the part played by 

 mitochondria in the development of the specific granulations in leucocytes has 

 been touched on (p. 126), but nothing whatever has been done on the changes in 

 the mitochondria in blood diseases in man or in different experimental conditions 

 in animals. 



URINO-GENITAL SYSTEM. 



The kidney has been very carefully stucUed and the part played by the mito- 

 chondria in the formation of urine carefully worked up, for wliich see page 126. 

 Little, however, has been done on pathological changes in the kidney. 



Takaki (1907, p. 250) has made a study of autolytic changes by Altmann's 

 method. It is questionable whether Pizzini's (1908, p. 108) observations relate 



