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E. V. COWDKY 



four to thirty-six hours. We have no evidence whatever from other 

 sources beaming on this important point. 



Cells in Colloid. The presence of a few desquamated epithelial cells 

 in the colloid substance within the follicles can hardly be regarded as 

 abnormal. When, however, it is very marked, care must be taken to ex- 

 clude the possibility of post-mortem change. We occasionally find in 

 the colloid substance erythrocytes and pigment produced through their 

 disintegration. 



Fig. 6. Section of an opossum's thyroid showing two types of cells and intracellular 



crystalloids, after Bensley. 



In the living state, teased out in salt solution, the secretory cells 

 present a fairly uniform appearance in man. 



Cytology. Each cell contains a spherical nucleus with prominent 

 nucleoli. In the cytoplasm droplets of colloid and occasionally of fat 

 may bo seen. The mitochondria are hard to distinguish, unless a little 

 janus green is added to the solution; this quickly stains them a bright 

 bluish green. 



Mitochondria. Under normal conditions the mitochondria occur in 

 the form of filaments about 0.2 ^ in diameter and varying in length from 

 0.2 to 4.0 ^. They are usually disposed parallel to the long axis of the 

 cell, and are most abundant in the distal zone of the cell, next to the 



