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Journal of Agricultural Research 
Vol. IX, No. s 
varies widely. These granules are not as large as the red granules found 
in the eosinophiles. 
Gruner 1 speaks of this kind of a mast cell as a true mast cell. Such 
cells have a narrow cytoplasm. The granules vary in size. He states 
that these cells are lymphocytes which have undergone mucoid degener¬ 
ation. 
In the blood of some pigs the mast cells are quite large, the nucleus 
usually bilobed, a large amount of cell space is visible, and the granules 
are slightly larger but not as numerous as in the cells first described. 
Transitionals. —Dinwiddie 2 recognizes a classification of transitional 
leucocytes. Occasionally true and distinct transitional forms of leuco¬ 
cytes are met with in the blood of the pig, but we have followed the cus¬ 
tom of most workers and have classified them in one group of the related 
type. True transitionals would very likely represent about i to 2 per 
cent of the total leucocytes, but there would be many border-line cases, 
and it would be difficult to know just where to place them. Individual 
workers would very likely differ widely in classifying them, and we have 
found it much easier to place them in the recognized group which they 
most closely resembled. Therefore, when these cells were encountered, 
they were either added to the large mononuclears, lymphocytes, or 
polymorphs. 
Blood platelets. —No attempt was made to estimate the number of 
blood platelets per cubic millimeter. Blood plates occurring singly and 
in clumps are often encountered in the dry spread. When Wright's 
stain is used, the blood plates take a bluish tint and show many dark 
granules. The blood platelets which are encountered singly vary in size 
and shape. They may be round, oval, or irregular; some are smaller, 
and others are larger than an average-sized red corpuscle. When in 
clumps, the individual size, shape, etc., can not be determined. 
Erythrocytes. —In a well-stained spread the erythrocytes are red in 
color and are circular. Willey, working in this laboratory, found 
nucleated red corpuscles in the blood of a 4-weeks-old pig. 
Effects of age. —Observations made by different workers relatively 
to the effects of age upon the number of red blood cells are conflicting. 
Storch 3 reports the number in adult swine to be 8,045,000 and in young 
pigs (6 to 35 days old) 4,923,000. 
Giltner’s 4 table shows a higher red-cell count in young pigs (2.5 months) 
than in the older animals, averaging 8,363,333 erythrocytes for the young 
and 7,322,500 for the older. The leucocytic count was about the same 
in the two groups. 
Our results are more in accord with those of Storch. The red cor¬ 
puscles showed an average of 3,853,071 cells per cubic millimeter in the 
1 Gruner, O.C. Biology of the Blood-Cells . . . p. 259. London, 1913. 
2 Dinwiddie, R. R. Op. cit. 
3 Burnett, S. H. Op. cit., p. 48. Cites paper by Storch. 
4 Giltner, Ward. Op. cit. 
