isr. TllK AM I:KH AN MONTIILV |.lnly, 



oils rrralurcs aU'I iiuy an' loixeti to swmIIdw lar'^c i|uantilii's of 

 watrr. What lu'coiurs of it? Is it rcjiurjiitatfd tlir<)»i<:li tlu' 

 pharynin'al passairr and the oral aptM-turc? If it is, then it 

 |>asses up ajxainst a pciwcrfiil ciliary curroiit setting in in tin* 

 oppositr tlinrtion. If tlu'n- should hv no way of dis|)osin<; of 

 it, would not the cvor-hun^rry croaturcs hcooino dropsical to the 

 point of explosion? The fact is that they never do. 



It is the generally accepted hclief of niicroscopists that the 

 invi«<ihle channels rainifyinj; throughout the endoplasni (•(•llfcl 

 this litjuiil and carry it, with any excretory products, to thi' 

 contractile vesicle whence it is expelled into tlie surrounding 

 wat«'r. It is not easy to color the c()ntents oi this contract- 

 ing organ, yet it has heen done. It is no light task to detnon- 

 8trate that its contents hold uric acid in solution, yet that has 

 heen done. Such experiinenis fail oftener than they succeed, 

 hut they do succeeil. I do not thinlc that a gas could he stained. 



The-e canals are supposed to he neither permanently (ixed in 

 one position nor to have a special lining nieinl)rano, being, in 

 the latter respect, like the contractile vesicle itself. It is helieved 

 that they oi)en anywhere within tiie endoj)lasni, througii wliich 

 they may not take the same course twice in succession ; and 

 that the fresh water ind>ihed with the food, and that jihsorhed 

 through the hody-surface, at some time surrounds every part- 

 icle of protoplasm in the organism, and gives to it its net;ded 

 oxygen, taking in exchange the useless excretory products and 

 carrying them to the contractile vesicle, whence they are ex- 

 pelled. If the protoplasm of the Infusoria is reticulated, as it 

 probably is and as that of Pelomyxd paliistris and of the Amceba 

 surely i.s, then these channels are not necessaiy to explain the 

 collecting of the liquid, for if the reticulated structure exists, 

 the circulation of the water amid tiie meshes of that living net- 

 work would be a beautiful contrivance, and would rend(;r super- 

 11 nous the formation of water-canals anywhere excejU near the 

 contractile vesicle to lead the liquid into it. This is the ar- 

 rangement which I believe to l)e present, although it is not 

 possible to do anything whatever t )Wiird demonstr iting it. Yet 

 it explains certain phenomen I readily observable, and other- 

 wise not readily accounted for. 



Uric acid cr}slals, or what amounts to the same thing, murex- 

 ide crystils, have been seen within the contractile vesicles of the 



