February 17, 1922] 



SCIENCE 



185 



system in whorls. They reach the surface of 

 ridges which appear as papillae because they 

 are cut across at regular intervals by the 

 longitudinal ciliary grooves. 



The morphology of tliis neuromotor appara- 

 tus shows that it is well adapted to coordinate 

 the movements of the animal because the 

 organelles of feeding, locomotion, and defense 

 are all connected by a system of conduetile 

 fibers to a presumably coordinating center. 

 Furthermore the fibers must be either support- 

 ing, contractile, or conduetile. Their exceeding 

 fineness indicates the unlikelihood of a sup- 

 porting function. Their position with respect 

 to the neuromotor center makes it unlikely that 

 they are contractile because those, the main 

 direction of which is longitudinal, would have 

 to operate antagonistically to those whose 

 direction is transverse. The only alternative is 

 that the fibers are conduetile. 



Three experimental methods, that of stain- 

 ing by micro-injection, the determination of 

 the axial gradient in solutions of narcotics 

 (Child, 1915), and micro-dissection (Taylor, 

 1920) were used to secure additional evidence 

 pointing towards a neuromotor function of 

 the fibers. 



Experiments with the first method were 

 negative. An axial gradient was easily demon- 

 strated, indicating the presence of conduetile 

 elements. A high rate of metabolism in the 

 region of the neuromotor center could not be 

 demonstrated, however, because Paramecium 

 did not disintegrate as do annelid worms and 

 planarians in the solutions used. 



Cutting the cytopharyngeal fibers resulted 

 in the loss of coordinated movement of the 

 eytopharj'ngeal membranelles. Extensive 

 destruction of tissue in the region of the neuro- 

 motor center resulted in the loss of coordinated 

 movement of locomotor organelles. Equal 

 destruction of tissue elsewhere in the body did 

 not destroy coordinated movement. 



Thus, while experimental evidence is less 

 conclusive than the morphological it supple- 

 ments the latter in demonstrating that the 

 fibers of Paramecium have a conduetile func- 

 tion. 



Charles W. Rees 

 Zoological Iiaboratory 



University of California 



THE AMERICAN CHEMICAL 

 SOCIETY 



(Continued) 



section of leather chemistry 

 John Arthur Wilaon, chairman 

 G. D. McLaughlin, secretary 



Color measurement of vegetable tan liquors: 

 Henry Richardson Procter. 



The color value of a tan liquor as a function of 

 the hydrogen-ion concentration: John Aethxir 

 Wilson and Erwin J. Kern. The color value of 

 a tan liquor depends upon its hydrogen-ion con- 

 centration when used. A change in pH value 

 produces a change in color of both liquor and 

 leather. Tan liquors change in color like indica- 

 tors with change in pH value, but over a range 

 of from 3 to 12. This change in color is com- 

 pletely reversible, if the liquors are not long ex- 

 posed to air. Liquors exposed to air continue to 

 darken in color, the more so the higher the pH 

 value, but this change is not reversed by lowering 

 the pH value. Liquors exposed to air at pH 

 values of about 9 give bulky precipitates when 

 their pH values are brought to 3 and such liquors 

 tend to poison the hydrogen electrode. 



Chemical and physical behavior of gelatin solu- 

 tions: Jacques Loeb. 



The equilibria between tetrachrome collagen 

 and liquors of different chrome content: Arthur 

 W. Thomas and Margaret W. Kelly. 



The adsorption of the constituents of chrome 

 liquor by hide substance during nine months con- 

 tact and the equilibria between tetrachrome colla- 

 gen and various concentrations of liquor: Arthur 

 W. Thomas and Margaret "W. Kelly. Previ- 

 ously a tetrachrome collagen was considered the 

 most complex chrome collagen compound obtain- 

 able. In this research an oetachrome collagen 

 was prepared. Further it was established through 

 study of the change in composition of tetrachrome 

 collagen in contact with liquors of different con- 

 centrations over a period of nine months that the 

 reactions taking place in chrome tanning are 

 chemical in nature. This paper is one of a series 

 of contributions from this laboratory establish- 

 ing the chemical nature of the combination of 

 chromium with hide to form chrome leather. 



Influence of sodium chloride, sodium sulfate 

 and sucrose on the combination of chronvic ion 

 with hide substance: Arthur W. Thomas and 

 Stuart B. Foster. Until four years ago it was 

 considered that the only important features 

 involved in the use of chrome liquors in chrome 

 tanning was the percentage of chromium and 



