202 JEREMIAH S. FERGUSON 



formed to such a state that it may be secreted through the wall 

 of the follicle, in which case the intrafollicular colloid would pre- 

 sumably assume the nature of stored secretion which is first poured 

 out from the cells as a fluid, is then condensed through retention 

 within the folhcle, to form colloid, and is later disintegrated, pass- 

 ing out of the follicle with the secretory flow. The chemical analy- 

 ses of the thyroid gland, showing the common relation of iodin 

 to the colloid and to the active principle of thyroid secretion 

 would hannonize with such an hypothesis. 



Vacuolation of the colloid mass (fig. 14) is of frequent occur- 

 rence; it may result either from the inclusion within the intra- 

 follicular colloid of portions of the peripheral cup-like impressions 

 which Langendorf has surmised result from the secretion pouring 

 out fiom the surface of the epithelial cells, or it maj^ be further 

 evidence of disintegration of the colloid with formation within 

 its substance of fluid droplets, rather than of solid spherules. 

 The vacuoles are filled with a clear fluid and occasionally contain 

 basophile granules. A colloid mass may contain many small 

 vacuoles mostly at or near the periphery of the mass and contain- 

 ing few, if any, basophile granules, or it may contain one or more 

 vacuoles of relatively large size which occupy the interior of the 

 mass and may be more or less completely filled with the granules. 

 These granules stain deeply with hematoxylin and similar dyes, 

 and they are either amorphous or somewhat crystalline in form. 

 The origin of the chromatic material within the vacuoles may be 

 from chromatolysis of the nuclei of either the disintegrating folli- 

 cular epithelium or of blood cells included within the colloid. 

 Evidences of disintegration of epithelium and extrusion of the 

 nuclei as well as of the penetration of the nuclei together with 

 blood cells (fig. 20) into the colloid mass are frequently seen. But 

 the disintegration of such cells and nuclei can scarcely account 

 for the much more numerous vacuoles in which no basophile 

 chromatic substance is found. 



The follicles of the thyroid are supported within the meshes of 

 a connective tissue stroma in which the blood-vessels lie. The 

 volume of connective tissue is never great, much less than in the 

 mammalian gland. There is more connective tissue in the gland 



