February 1, 1895.] 



SCIENCE. 



110 



ance both positively and negatively with 

 those announced by Kenier. 



There had been foniul a great dift'erence 

 in the degree of eortieal development of 

 mammals not born blind as compared with 

 those born with the eyes unopened: but as 

 the work was not complete the author pre- 

 ferred not to make many very definite state- 

 ments at the present time. Cortical devel- 

 opment and psychic development took place 

 pari pa-^'^ii . 



The Active I'rinriple of lihus Tox-ieodcwh-oii 

 ami Jilutx Veiieiiatii. Franz Pfaff. (In- 

 troduced by H. P. BowDiTCH.) 

 Dr. Pfofi' stated that his experiments had 

 been made with the assistance of S. San- 

 ford Orr. He said that it is the general 

 opinion that Bh. tojc. and Ek. ven. con- 

 tain a volatile proximate principle, which 

 causes the well-known dermatitis venenata. 

 Maisch's toxicodendric acid has been gen- 

 erally accepted as tlie active poison. P. 

 and 0. could not believe that a very Aola- 

 tile substance is the cause of the trouble, 

 as this would be contrary to the phai-macol- 

 ogy of vegetable skin irritants. They iso- 

 lated Maisch's toxicodendric acid in the 

 form of the barium salt, and found it non- 

 toxic. The same is true of a solution of 

 the free acid in water. As the real active 

 principle they found a non-volatile oil. This 

 oil, when applied to the skin, causes the well- 

 known eruption. Photographs demonstrat- 

 ing the effect of the oil upon the human skin 

 were shown. As preventive treatment P. 

 and 0. proposed a thorough washing with 

 water, soap and brush, or, still better, a re- 

 peated thorough washiug with an alcoholic 

 solution of lead acetate. The oil being sol- 

 uble in alcohol, and forming a nearly insol- 

 uble lead compound in alcohol, is thus best 

 removed from the superficial skin. Fui'ther 

 investigations will be undertaken, and an 

 attempt made to classifj' Maisch's toxico- 

 dendric acid and the new poisonous oil. 

 which seems to be of the kind called cardol. 



obtained from Anacardiwn occidentale. These 

 two oils are, however, not identical. 

 Inhibition Hypothe/tix in the Phyniology of Res- 

 piration. AV. T. Porter. 

 Dr. Porter said that it is known that 

 transverse division of the spinal cord be- 

 tween the bulb and the phrenic nuclei 

 causes fatal arrest of the respiratory move- 

 ments of the trunk. If death be prevented 

 for a time bj^ artificial respiration, the re- 

 flex powers of the cord gradually increase, 

 and in the coui-se of a few hours they maj' 

 become so great that pinching the paws, 

 blowing on the skin, suspending the artifi- 

 cial respiration, etc., may cause extended 

 muscular conti-actions, including contrac- 

 tions of the respiratory muscles. 



It is claimed that these contractions of 

 the respirator}- muscles after the separation 

 of the cord from the bulb are proof that the 

 respirator}' impulse for muscles of the trunk 

 is not derived from respiratory cells in the 

 bulb but originates in the spinal cord. 

 Against this hypothesis of .spinal respiration 

 is urged the fatal arrest of the respiration 

 of the trunk caused by separating the bulb 

 from the cord. It is replied that section of 

 the cord stimulates inhibitory fibres in the 

 cord and thus suspends the action of the 

 spinal respiratory cells. This inhibition, it 

 is assumed, usually lasts throughout the 

 period of observation ; in some animals, 

 however, after long artificial respiration, it 

 is partially overcome, permitting the resi>i- 

 ratory contractions mentioned above. 



The doctrine of prolonged inliil)ition of 

 spinal respiration is easily overtlirown by 

 the following experiment. Hemisection of 

 tiie cord usually arrests the contractions of 

 the diaphragm on the side of the hemisec- 

 tion. ( Exceptions are explained by ' crossed 

 respiration.') This arrest is not an inhibi- 

 tion, for the diaphragm on the side of the 

 hemisection begins at (mce to contract when 

 the opposite phrenic nerve is cut. Hence, 

 hemisection of the cord between the bulb 



