ORIGIN OF PHAGOCYTIC MONONUCLEAR CELLS BY A 
are present 2.66 per cent mononuclear cells with carbon and 8.85 
per cent of polymorphonuclears containing it. Twenty-two and 
one-half hours after the fifth injection no carbon containing 
cells are present. One hour after the third injection no carbon- 
containing mononuclear cells are found. 
Rabbit 164 was the first to receive both citrate and lampblack, 
and for the first time a distinct number of carbon-containing 
cells are present in the peripheral blood of a rabbit after a single 
injection. After application of the method used for determining 
the number of phagocytic mononuclear cells in human blood 
TABLE 1 
DURATION DOSE OF TIME KILLED 
NO. , ANIMAL Peeve oe DOSE OF CARBON CITRATE eT aee 
1 Rabbit 1 da. 2.25 ec. once 0 24 hr. 
138 Rabbit 3 da. 1.5 ec. three times 0 10 min. 
139 Rabbit 7 da. 1.5 ce. six times 0 i aie: 
151 - Dog 9 da. 10.0 ec. seven times 0 5 hr. 
164 Rabbit 30 min. 5.5 ec. once 5.5 ec. | Not killed 
176 Dog 1 da. 9.0 ce. once 9.0 ce. 24 hr, 
200 Rabbit lene. 2.0 ec. once 4.25 ce. 1 hr. 
201 Rabbit 30 min. 3.0 ce. once Gafolices 30 min, 
205 Rabbit PD \ oie: 2.5 ec. once 5.0 ce. PB Sour 
208 Rabbit 24 hrs. 1.0 ee. once 3.5 ec.| Dead 24 hr, 
209 Dog 1 da. 3.0 ce. once S0mees 24 hr. 
212 Rabbit 1 da. 1.75 ce. once 4.5 ce. 24 hr. 
213 Rabbit 1 da. 1.5 ec. once. 0 24 hr. 
1 Citrate contains opalescent suspension typhoid bacilli. 
(McJunkin, 718) variations between 1.09 and 4.7 per cent of 
these cells are found in the peripheral blood of rabbits. The 
next animal to receive the lampblack and citrate was a dog 
(176). The smears made at the end of one hour are not satis- 
factory and an accurate count cannot be made. 
A count of 595 cells in the peripheral blood of rabbit 200 taken 
one hour after injection shows 3.03 per cent mononuclear cells 
with carbon together with 2.02 per cent carbon-containing poly- 
morphonuclear leucocytes. Of 1026 cells in the blood of rabbit 
201 thirty minutes after injection 2.63 per cent are mononuclear 
cells containing carbon with only 0.97 per cent polymorpho-. 
nuclear carbon-containing ones. In rabbit 205 two hours after 
