COMMON CHEMICAL SENSE 7 



SUMMARY 



1. There is positive evidence, in the case of alkalies, acids, 

 and certain salts, that solutions supplying stimuli for the com- 

 mon chemical sense do not penetrate the skin of aquatic animals, 

 nor when applied from a pipette do they damage the skin to any 

 extent. 



2. There is consequently no ground for Coghill's assumption 

 that the cells of the germinative layer of the epithelium of fishes 

 and amphibians are exposed to the action of the stimulating 

 agent and thereby disrupted; and there is no histological evi- 

 dence of disruption. 



3. The reactions attributed to the common chemical sense 

 depend upon a group of sense organs distinct from those sensi- 

 tive to mechanical stiimilation. 



UKKi;ui:xcEs 



BuAEUNiNG, H. 1904 Zur Kenntnis dcr W irkunj; chi'misclicii Hcizc. Arch, 

 gcs. Physiol., lid. 102, p. 163 1S4. 



C'ocaiiLL, G. E. 1914 Correlated anatomical and physiological studies of the 

 growth of the nervous system of Amphibia. I. The afferent system 

 of the trunk of Amblystoma. Jour. ("omp. Xeur., vol. 24, p. 161-233. 



Cole, h. W. 1910 Reactions of frogs to chlorides of ammonium, potassium, 

 sodium, and lithium. Jour. Comp. Xeur., vol. 19, p. 273-311. 



Crozikh, W. J. 1915 a The behavior of an enteropneust. Science, X. S., vol. 

 41, p. 471-472. 



(Note — Lines 5 and 6 [p. 472] have i)een accidentally interchanged by 

 the printer.) 



1915 b The rhythmic pulsation of the cloaca of holothurians. Ibid., 

 p. 474. 



1915 c The sensory reactions of Holothuria surinamensis. Zool. 

 Jahrb., Abt. Physiol. [Xot yet published]. 



1915 d On cell penetration by acids. Science, X. S., vol. 42, p. 735- 

 736. 



Hakvey, E. X^. 1910 Studies on the permeability of cells. Jour. Exp. Zool., 

 vol. 10, p. 507-556. 



1914 Cell permeability for acids. Science, N. S., vol. 39, p. 947 949. 



Herrick, C. J. 1908 On the phylogenetic differentiation of the organs of taste 

 and smell. Jour. Conip. Xour., vol. 28, p. 157-166. 



