334 THE AMERICAN MONTHLY [Dec, 



The Action of Leucocytes Toward rorci)j;n Material. 

 By kdith j. ci.Avrou:, 



\KUON. OHIO. 



In this ji;i|Mr tic results of ?oine oxpcriiiuMit? iiiadoin the lab- 

 oratory of Profcs-or Gnpe of Corn* 11 I'nivrrsity, duriiisr the jiast 

 year nreluifily set fort li. The objrct of the experiments was 

 twofohh In the firpt plnoe, to discover ifpoFsil)i(! the ultimate 

 fate of at least i)art of ihe preat number of leucocytes that in 

 the airnial I ody continually ]i:iss away frr>m the circulation', 

 and in the second place to find what part the leucocytes play 

 in the removal of fore! en material from the body. 



In considerinu' this second ])oint the nature of the leucocytes 

 as entities in the eeonom}' of the animal system is of especial 

 importance. The Phajiocyte Theory of the preat IJussian mar- 

 pholopist. MetschnikofI'. is l)ased on one of their peculiar pow- 

 ers, tiiat of takinp up foreipn m iterial by virtue of tin ir amoe- 

 boid niovemej t. Th« se cells form the guardian army of the 

 body. They stand ever ready to inpest and remove all foreign 

 substances that enter the system, and on their al)ility to do so 

 depends, to some extent at least, the health of the animal. If 

 theinvadinp forc(saretoo stronp, the animal becomes sick or 

 perhajis dies, but if victory is with the leucocytes normal condi- 

 tions are again established. 



It is not necessary, however, for the contest to Itecome ap])ar- 

 ent. It is continually taking place, often giving no external evi- 

 dence of its existence. 



Such is the Phagocyte doctrine as its founder taught it. As 

 in other ca^es of wide generalizations, these extreme views have 

 not been adopted by al'. Those belonging to the more conserva- 

 tive party consider the protective part played by the leucocytes 

 as small or merely incidental. The fact of the ingestion of the 

 foreign material remains established, however, and on the 

 strength of this knowledge the following experiments were made, 

 the results of which are briefly presented. 



Under as nearly normal circumstances as possible, a smal' 

 quantity (1-1 com.) of a mixture of lamp-black and gum ara- 

 ble suspended in normal salt solution, was hypodermically in- 

 jected into the abdominal cavities of the sal imanders, NerUinin 

 maculatus (Mud-puj>pyj and Cryjiiohrfinrhu.i (dlcijlianinuis (HelJ- 



