234 A. L. HERRERA [march 1899 



one, may result in certain nervous and continuous actions or sensa- 

 tions, external stimuli provoking the vibrations, as I have studied in 

 mercury. 1 On the other hand, Dubois says that anaesthetics produce 

 the expulsion of internal water, and I have observed that exhalations of 

 ether have the property of energetically repelling any thin layers of 

 water (" On a Property of Ether," Mcmorias y Bevista Sociedad Alzate, 

 1895-96, Nos. 5, 6, p. 33). This means that anaesthetics modify the 

 rapidity of the currents or even succeed in completely preventing them. 



The action of alcohol on my artificial product is curious, there 

 being a remarkable excitation of the movements followed by their 

 absolute paralysis. 



In the sea-urchin egg, says Dubois, segmentation can be pre- 

 vented by hindering hydration by the addition of salt at 2 per cent, 

 to the sea water. When segmentation has already begun it stops in a 

 strongly salted medium, but it pursues its course directly after some 

 normal water is poured on it ; and, what appears more notable, it then 

 continues with increased rapidity. I have observed analogous phenomena 

 in my artificial protoplasm. 



In a word, the protoplasmic currents have a constructive or forma- 

 tive action comparable to that wrought by rivers on the earth's surface. 



Contractile vacuoles can be explained by an augmentation of 

 tension promoted by some endosmotic currents. The former may be 

 imitated by alternatively stretching and relaxing a plate of gluten. 



Life ought not to be likened to a continuous chemical reaction, the 

 mechanism of which remains involved in darkness and unexplained. 

 Life is now to be defined as the result of the physico-chemical action 

 of protoplasmic currents, the cause of such currents being diffusion, 

 heat, and some other secondary factors. Death consists in an absolute 

 suspension of the internal currents in general ; latent life is character- 

 ised by the establishment of the said currents under the influence of 

 oxygen, heat, and water, in a germ or organism having the structure 

 and chemical elements necessary, and supplied with every nutriment 

 required. Oscillating life is nothing more than an alternate contribu- 

 tion and reassertion of the constructive internal currents, depending 

 upon the variations of the external temperature. Every physico- 

 chemical or mechanical action capable of affecting the rapidity, 

 direction, and other characters of internal currents must have more or 

 less influence on the phenomena hitherto considered as vital. 

 Mexico, January 9, 1899. 



[It may be recalled that the artificial protoplasm to which the 

 author so often refers is an emulsion of albuminoid, etc., made according 

 to Eeinke's analysis of " Flowers of Tan." In expounding his conclusions 

 Professor Herrera is at a disadvantage in writing in a foreign tongue ; 

 and we may also note that he is also hindered in his researches by the 

 lack of an adequately powerful microscope. — Ed. Nat. Sci,]. 



1 Natural Science, December 1898. 



