2 G. L. KITE. 



A number of methods were used in order to make the data 

 comparative and to determine the error and limitations of a given 

 method employed. The effect of various operations, such as 

 partial dissections, and punctures, on the permeability and os- 

 motic properties of cells was studied. Intracellular injections 

 were made by Barber's method. 1 



THE PERMEABILITY OF ANIMAL AND PLANT CELLS TO ACID 



DYES. 



Incidental to this study, a number of facts bearing on Over- 

 ton's so-called lipoid theory have been determined, and as animal 

 physiologists have taken kindly to this notion some of these data 

 will be given. 



Rhuland 2 and others have shown a number of exceptions to 

 Overton's 3 conclusion that cells are impermeable to lipoid in- 

 soluble acid dyes. 



By using a large number of species of animals and plants from 

 widely separated genera and phyla, I have found it quite easy 

 to discover cells that are freely permeable to many lipoid - 

 insoluble acid dyes. Such well-known acid dyes as eosin and 

 trypan red are good vital stains for Mucor and Saprolegnia. 



The lipoid-insoluble acid dyes used include: 



Trypan blue, which penetrates the eggs of Nereis and Chatop- 

 terus, the root-hairs of barley and the Windsor bean, immature 

 Necturus eggs, the peritoneal epithelium of Necturus, Ameba 

 proteus, Paramecium, Mucor, and Saprolegnia. 



Trypan red : the eggs of Cumingia and Ch&topterus, the root- 

 hairs of barley, the edible pea and the Windsor bean, Ameba 

 proteus, Paramecium, Mucor, and Saprolegnia. 



Isamin blue: the root-hairs of barley and the Windsor bean. 



Analine blue: the eggs of Choetopterus, the root-hairs of barley 

 and the Windsor bean, and Mucor. 



Acid fuchsin: The root-hairs of barley, the Windsor bean and 

 Mucor. 



Acid green : Saprolegnia and Mucor. 



1 Barber, Jour, of Inf. Dis., 1911, VIII., p. 348. 



2 Jahr. Wiss. BoL, Bel. 51, H. 3, p. 376. 



3 Jahr. f. Wiss. Bot., Ed. 34, 1900, p. 669. 



