336 



Scientific Proceedings (123). 



end, that irritability was retained by the posterior dissected por- 

 tion of the cord for more than 45 minutes. Since it is possible 

 to complete a respiration experiment in 20 minutes, the tissue 

 must have been irritable throughout each experiment. 



The procedure consisted first in determining the rate of C0 2 

 output for the resting cord. The effect of activity on the respira- 

 tory rate was found by suspending the tissue in the indicator tube 

 on platinum electrodes which were passed through a paraffined 

 stopper, and then stimulating the cord with induction shocks while 

 the reading was being made. The current used for this purpose 

 was not sufficient of itself to cause any change in the tint of the 

 indicator, no matter how long continued. A third reading was 

 now made with the tissue at rest. The relative rates of respira- 

 tion in the three cases were determined by calculating the second 

 and third readings as per cents, of the first. Averages of ten 

 experiments made on the nerve cords of as many different animals 

 yielded the following result: Resting 100 per cent., stimulated 

 89 per cent., resting 86 per cent. Electrical stimulation, there- 

 fore, not only did not increase the rate of CO2 production of the 

 nerve cord of Cambarus, but failed to interrupt the normal fall in 

 rate. The question may thus rightly be raised whether functional 

 activity of the cells of the central nervous system of the cryfish is 

 accompanied by increased metabolic activity. 



160 (1907) 



The value of intratracheal route of immunization with pneumo- 



coccus. 



By J. BRONFENBRENNER and E. KNIGHTS. 



[From The Department of Preventive Medicine and Hygiene, Harvard 

 Medical School, Boston, Mass.] 



The ease which with gases diffuse through the respiratory 

 mucosa is well known and is widely utilized in the practice of 

 anesthesia. The absorption from the trachea, however, is not 

 limited to gases. Thus, Mayer 1 found potassium ferrocyanide in 



1 Muller, Manual de physiologic Paris, 1851, p. 186. 



