MEDEARIS AND MARBLE: THYMUS GLAND. 143 



Comparisons Made to Correlate the Size of Underdeveloped 

 AND Overdeveloped Pigs with the Size of the Thymus, Tak- 

 ing Percentage of Thymus by Weight as a Standard, and 

 Grading Pigs in the Litters by Weight. 



As the title above indicates, table No. 7 is the result of an attempt 

 made to correlate the size of underdeveloped and overdeveloped 

 foeti with the size of the thymus, taking percentage thymus by 

 weight as a standard, and grading pigs in the litters by wcigiit. In 

 each litter the two smallest fa?ti (by weight) and the two largest 

 were studied as to percentage thymus by weight as seen in column 

 F in the table. The percentages of the two smallest and the two 

 largest were individually averaged (column G), and the two aver- 

 ages compared; the correlation noted was recorded in column H. 

 Positive or + correlation is taken to mean that the overdeveloped 

 pigs in the litter had a greater percentage of thymus than the under- 

 developed pigs. As seen from the table, there were ten positives and 

 eight negatives. This is indeed a very weak positive correlation; so 

 slight, in fact, that we feel that it must be disregarded until more 

 positive data can be secured. Hence, once more we must decide, on 

 the basis of the data at hand now. that no parallelism exists between 

 the large and small size, respectively, of underdeveloped and over- 

 developed fa?ti and the percentage of thymus by weight. 



