464 BOTANICAL GAZETTE [December 



is exhibited, the stimulated portion being positive w ith reference to the other. 

 Several curious and apparently very important analogies between the 

 electric responses in plant tissues and corresponding ones in those of animals 

 were brought out. (i) In stale nerve the current of response is the reverse 

 of what it is in fresh ; it flows from the less excited to the more excited, but 

 with very strong stimulation the response becomes again like that in the fresh 

 material. Exactly the same phenomena are observed in plant tissues. (2) 

 Decrease in temperature causes decrease in response in animals. In plants 

 this is also true where the tissue is otherwise known to be easily affected by 

 cold. But in hardy plants a lowering of temperature, unless it nears the 

 death point, does not have much affect. (3) High temperatures nearing the 

 death point produce a fall in the intensity of response in both animals and 

 plants. This electric method furnishes an immediate and direct means of 

 determining the death point, for here and beyond no response can be obtained. 

 (4) Anaesthetics and poisons have the same effect on the electric response in 

 plants as in animals. With the application of the reagent the response is 

 gradually depressed until it finally ceases altogether. (5) In some cases of 

 poisons where a large dose produces depression and annihilation of response, 

 a small dose acts as a stimulating agent and produces a rise in the response 

 curve. This is also known in some animal tissues. 



These results seem to be almost a proof of the underlying identity, or at 

 least remarkable similarity, of plant and animal protoplasm, and hence are to 

 be regarded as exceedingly important and fundamental. I cannot resist the 

 temptation to suggest here, in view of the long-continued discussions as to the 

 point where life gives place to death, that we have perhaps in this electric 

 response the best criterion yet discovered for determining when a tissue is 

 alive and when dead. An arbitrary definition of life might be an aid in some 

 cases, and probably the best one which can be framed (if the properties 

 here described are shown to be general) is that protoplasm is alive when it 

 exhibits electric currents of response. — Burton E. Livingston. 



Recent studies upon regeneration : T, H. Morgan (Columbia Univ. 



Biol. Series VIII. The Macmillan Co., N. Y. 1901) has published a volume 

 dealing with regeneration in general, especially in animals. Chapter four is 

 devoted to regeneration in plants, and the familiar work of Vochting and 

 Goebel is cited, though practically nothing that is new is introduced. Morgan 

 holds, as do most authors, that in plants a latent bud develops, while in animals 

 there is a restoration at the cut surface. He does not accept Goebers idea 

 that this is due to the fact that plants have latent buds and hence do not 

 have to restore the lost part as do animals. He opposes Sachs' theory of 

 '* Stoff und Form," as well as Goebers modification of this theory; buds do 

 not remain latent because poorly fed, nor do they grow because they are well 

 fed. Morgan fails entirely to accept natural selection as a cause for the 

 development of the capacity to regenerate; organs which are not subject to 



