1889] Zoology. 819 
John Macoun. — "The Ligneous Plants of the Dominion of 
Canada." 
John M. Coulter. — "The Distribution of North ^ 
belliferffi." 
L. M. Underwood.—" The Distribution of North i 
The present secretary of the section is requested to give formal noti- 
fication of the persons named, and the secretary of the section for 1890 
is hereby requested to give such attention to this matter as may be 
necessary to perfect the proposed programme by correspondence, and 
through the circulars of the permanent secretary of the Association. 
The next meeting will be held in Indianapolis, beginning August 21. 
Charles E. Bessev. 
ZOOLOGY. 
The Doctrine of Phagocytes— The interest excited by the 
ingenious hypothesis of Metschnikoif is shown by the number of 
experiments made and the articles written in support or contradiction 
of the assumption that the mesodermal cells of the Vertebrata 
inherit the capacity of absorbing and destroying pathogenic 
bacteria from their ancestors, the unicellular Amoebae, the mesodermic 
cells of Ccelenterata, Turbellaria, etc. The summary of Dr. H. Bitter's 
recent critique of the evidence pro and con is thus presented by the 
Journal of the Royal Microscopical Society. 
Unicellular lower animals, amoebae, and also the mesodermic cells of 
sponges, take up small plants into their protoplasm, and digest them. 
In more highly organized animals this intracellular digestion becomes 
extracellular and fermentative ; certain cells, however, still possess a 
capacity for picking up and dissolving foreign bodies. This contriv- 
ance is regarded by Metschnikoff as a special arrangement whereby 
harmful elements, especially pathogenic organisms, are prevented from 
penetrating the animal economy, the process being complicated by the 
resistance made by the parasite to digestion. Those cells which are 
able to digest foreign bodies are called phagocytes, and are farther 
subdivided into large and small. Infectious diseases are recovered 
