Apr. 30, 1917 
Morphology of Normal Pigs' Blood 
133 
times daily. If the pigs showed any sickness, as evidenced by loss of 
appetite or increase in body temperature, they were not used. All of 
the pigs listed in Table III were afterwards used in producing hog- 
cholera virus. 
The young pigs were taken from the pen, in which they were confined 
with their mother, to the operating room, and the various tests made or 
samples collected; following this, the young pigs were returned to the 
mother. The samples of blood were taken from the small veins in the 
ear, after applying alcohol and then shaving. The puncture was made 
with a sharp scalpel. 
The samples from the larger pigs were obtained in a similar manner, 
except that these pigs were confined in a special hog crate. The samples 
were obtained as nearly as possible at the same hour each day, 10 a. m. 
The puncture produced a good flow of cutaneous blood, and the first 
few drops were wiped away. It was usually necessary to make several 
punctures before completing the examination. 
The usual methods of study were employed. The percentage of 
hemoglobin was obtained by means of the Sahli hemometer. The blood 
for estimating the number of erythrocytes and leucocytes was drawn in 
the same pipette, and Toisson’s diluting fluid used as the diluting mixture. 
Two pipettes giving a dilution of 1 to 100 were used in each case, and 
both erythrocytes and leucocytes were counted on the same field. A 
count was made from each pipette, and, if the amount of variation was 
100,000 erythrocytes or less, the results were considered satisfactory and 
were recorded. The counts were made on the Thoma-Zeiss hematocy- 
tometer counting chamber with the Zappert-Ewing ruling. The leuco¬ 
cytes were sometimes estimated by the acetic-acid method, with a pipette 
of 1 to 10 dilution. The specific gravity was determined by the Hammer- 
schlag method. The time of coagulation was determined by means of 
the Biffi-B rooks coagulometer. 
In making the differential counts of the leucocytes Wright’s stain was 
employed as the staining agent, and 200 to 300 of the corpuscles counted 
on at least two spreads of blood, so that never less than 500 leucocytes 
were counted. 
RESULTS OF EXPERIMENTATION 
Twenty-five examinations were made of the blood of normal pigs 
between the ages of 2 and 42 days. The results of these examinations 
are shown in Table II. The average number of erythrocytes was 
3,855,000 per cubic millimeter, and 13,500 leucocytes per cubic milli¬ 
meter. The average clotting time was 64 seconds, specific gravity 1.024, 
and the average hemoglobin percentage 56.8. Differential count of 
leucocytes showed the following: Lymphocytes, 63.25 per cent; poly¬ 
morphs, 32.14 per cent; mononuclears, 2.63 per cent; eosinophiles, 1.28 
per cent; mast cells, 0.24 per cent. 
