1918] McNAIR—SECRETORY CANALS 273 
3. There are no essential differences in the arrangement of the 
intercellular secretory reservoirs between the poisonous and non- 
poisonous Anacardiaceae. 
4. From an anatomical santinaeel there is no reason why the 
poisons of the Anacardiaceae should vary either in physiological 
action or in chemical composition. 
5. The fresh sap emulsion is the only cart of the plant capable 
of producing dermatitis. 
6. Those portions of the plant that do not contain the resin ducts 
do not normally have this kind of toxic effect. 
7. The non-toxic portions are the anthers, pollen, xylem, 
epidermis, cork cells, and trichomes. 
8. The liability of poisoning from R. diversiloba tissues decreases 
as follows: immature leaves and flower parts (except anthers and 
pollen), mature leaves, green stems, young roots, woody stems, and 
woody roots. 
9. The liability of poisoning from R. diversiloba is greatest in the 
spring, less in the summer and fall, and least when the plant is 
leafless. 
PASADENA, CAL. 
LITERATURE CITED 
I. i fa Gummiharzang d. Lackbaumes, U.S.W. Bot. Centralbl. 3:352-. 
re McNars. James B., The transmission of Rhus poison from plant to person 
(Rhus diversiloba T. and G.). Jour. Infect. Diseases 19:429-432. 1916. 
3. , The oxidase of Rhus diversiloba. Jour. Infect. Diseases 20:485- 
498. 1917. 
4. Murr, Joun, My first summer in the Sierra. Boston and New York. ro11 
(pp. 34, 35). 
§. SIECK, W., Die schizolysigenen Secretbehilter. Jahrb. Wiss. Bot. 27:227. 
pls. 6-9. 1 
6. Sraveston, R. L., Napa wine III. - In the valley. The Silverado squatters. 
7. eo M. A., Des Vaisseaux propres dans les terebinthinees. Compt. 
Rend. 65:17. 1867. 
8. WIESNER, JuLIus, Die Rohstoffe des Pflanzenreiches 1: 
9. McNarr, James B., Pathology dermatitis venenata deat Rhus s deeraitebe. 
Jour. Infect. ieease 19:4190-428. 1916. 
