54 SUMMARY OF CURRENT RESEARCHES RELATING TO 



vital actions, even in organisms far inferior to the Ctenophora, defies 

 the present resources of physiologists. 



" The changeful phenomena of life, which we remark in the smallest 

 organisms — in the rhythm of their ciliary motions, now strengthened, 

 now slackened ; in the rhythmic alternation of the capacity of their 

 contractile vesicles ; in their regulated incomes, deposits, and expendi- 

 ture ; in the abundance of the visible products of their diverse material 

 exchanges — enable us but remotely to foresee what is here effected by 

 a harmonious co-operation of countless processes, limited to the 

 smallest space. Let their formal differentiation seem to us ever so 

 slight, just so do these beings become for us all the greater riddles, 

 especially when we find in them vital manifestations elsewhere dis- 

 played in the living world only by apparatus of the most highly 

 complex construction, and in them meet with processes which without 

 the orderly co-operation of very different factors must remain to us 

 unintelligible. Who would wish boldly to maintain, where even the 

 most delicate methods disclose to us merely what is homogeneous, 

 where quinine, in proportions scarcely perceptible by our nerves of 

 taste, transforms the entire protoplasmic mass of an animalcule into 

 an opaque albuminous particle, that the metamorphosis of tissue 

 proceeds according to one chemical formula, that living protoplasm 

 is a purely chemical substance, only excited and impelled by the 

 elementary bodies and the rigidly associated combinations of the 

 external world !" 



Rising and Sinking of Beroe.* — According to Eimer, Beroe 

 sinks by taking in more water than a vessel equal in capacity to the 

 living animal could hold ; the density of the liquid thus absorbed 

 augmenting amid the interstices of its loose gelatinous tissue, as within 

 a system of capillary tubes. But C. F. W. Krukenberg reminds us of 

 Eegnault's demonstration that a pressure of 200 atmospheres would 

 only reduce the volume of sea-water by 1 per cent. Moreover, the 

 living Beroe has a higher specific gravity than its environment. Its 

 rising, not its sinking, is the real problem. Poisoned Beroes sink at 

 once and stay at the bottom. Instead of repeating, with Eimer, that 

 a Beroe freed from water floats like a dry sponge, we should say that 

 the body, either of Beroe or of a dry sponge, must float when filled 

 with air, as even platinum would do if it held air enough. 



Krukenberg always found that non-vibrating Beroes remained 

 below. He will not, however, doubt Eimer's observation, that these 

 animals sometimes rest close to the surface of the water, with their 

 vibratory lamella3 in absolute stillness. Like Eimer, he would account 

 for this state of things by supposing an accumulation of gas. 



" Completely sharing Eimer's interpretation that the vibratory 

 lamellfe are truly such, but seeing that their movement is followed, 

 at one time by a rise, at another by an accelerated sinking of the 

 Beroe, one can only guess and is scarcely able to say what observa- 

 tions will decide this question, the answer to which no experimenter 



* Kiukenberg's ' Vergleichend-physiologische Studicn,' Part 3 (1880) pp. 

 147-50. 



