GENETIC TYPE AND THE ENDOCRINES 515 



With these points in mind, the parathyroid glands of the 

 bassethound-bulldog cross may now be examined. 



The histological pictures of the parathyroids from all bas- 

 sethounds are not exactly the same, yet they follow a some- 

 what common pattern. The epithelial arrangement gives a 

 fairly normal picture of lines and cords, seen in sections as 

 double rows of cells, and there are capillaries lying between 

 the cords and very little connective tissue. Almost all the 

 epithelium is of so-called principal cell type, with occasional 

 small groups and irregular masses of cells stained a dull 

 blue in color. 



Figure 1 in plate 97 illustrates a section of parathyroid 

 from the 6 year old bassethound bitch 277 9 . Near the upper 

 edge of the section a mass of sinusoidal capillaries is seen 

 as greyish spaces filled with laked blood and with elongate 

 endothelial nuclei at the borders. Lying among the sinusoids 

 are dark, almost black, masses of cells. These are the blue 

 stained cells which are frequently seen as dark streaks near 

 the periphery of the parathyroid and are of interest in the 

 present case in their intimate association with the complex 

 of sinusoidal capillaries. This is a rather frequent arrange- 

 ment. There are several small cysts with clear lumens in 

 this section, and the principal cells in the lower region form 

 numerous small circular arrangements which resemble fol- 

 licles but are merely circular bends in the cell cords. 



This parathyroid section is from a very prolific bitch which 

 had produced and successfully reared several litters of pup- 

 pies. The production and feeding of many puppies was no 

 doubt a severe strain on the calcium metabolism in this 

 animal, and the unusual degree of sinusoidal distention of 

 the capillaries in the parathyroid may have been associated 

 with this. It is interesting to note at this point that a forty- 

 five pound bitch, as was 277 9 , may whelp eight puppies, 

 each weighing one pound. This means that during the 60 days 

 of gestation she has produced animal substance weighing 

 eight pounds, or 17 per cent of her own total body weight. After 



