126 ON THE NATURE AND ACTION OF THE CROTALUS-POISON 



extravasation produced by Crotalus-wenom being well marked, 

 that by cobra-venom scarcely perceptible. In both cases the 

 microscope showed red corpuscles outside the vessels. 



These experiments show that Crotalus-'poison causes haemor- 

 rhage and haemorrhagic effusions more than the cobra-poison 

 does. 



The following experiments were made, at the suggestion of 

 Mr. Darwin, with the object of testing the influence of snake- 

 poison on ciliary action, especially in reference to its compara- 

 tive action on vegetable protoplasm, as will be seen by his 

 remarks. 



Experiment XXI. 



Influence of Cohra-poison on Ciliary Action. 



June 29th, 1874. — Ciliated epithelium from the frog's mouth 

 was treated with a solution of cobra-poison and examined under 

 the microscope. 



At 1.35 P.M., when examined, the action of the cilia was 

 vigorous. 



At 1.45 it was much diminished. 



At 1.55 it had entirely ceased. 



Experiment XXII. 



Ciliated epithelium placed under microscope ; one part was 

 treated with water, the other with the poisoned solution. 



At 2.10 P.M. ciliary motion vigorous in both, perhaps more so 

 in that subjected to the poisoned solution. 



2.18. Non-poisoned cilia active. Poisoned cilia very feeble. 



2.20. Non-poisoned cilia still active. Poisoned cilia very 

 feeble. 



2.24. Non-poisoned cilia active. Poisoned cilia very languid. 



2.30 Non-poisoned cilia still active. Poisoned cilia have 

 entirely ceased to act. 



It is evident from this that the poison first stimulates and 

 then destroys the activity of the ciliary action. 



