152 Proceedings of the Royal Irkh Academy. 



Towards the periphery of the mass the little orange-coloiired globules 

 acquire a more elliptic figure, and they can he watched passing up, 

 one by one, upon the tracks, where they assiime a fusiform figure, and 

 gradually, but very slowly, glide onwards. In the course of several 

 hoxirs, the greater part of these little bodies have ascended the tracks, 

 and slowly pursued their way to the margin of the drop of water. It 

 is therefore clear the little globules at fii'st seen, and the "spindles" 

 afterwards found travelling on the slender tracks, are identical. Their 

 contour is very delicate, they never become fused, though do not seem 

 to possess any evident membrane. The middle of each is occupied by 

 " a nucleus, appearing like a clear vacuole, enclosing a strongly refrac- 

 tive nucleolus;" they increase in number by self -division, and are 

 hence to be regarded as true " cells." Treated with tinctitre of iodine, 

 a sharply circumscribed contour makes its appearance on their surface, 

 becoming brown, and standing off, more or less, from the contents. 

 Alcohol chssolves the pigment, leaving the globules deprived of colour ; 

 the spindles so treated do not become blue by iodine, which at once 

 takes place when tincture of iodine is added to fresh material ; allowed 

 to operate longer, the whole spindle becomes dark brown. The beha- 

 viour of the pigment under sulphuric acid shows it belongs to the 

 category of colouring substances, fomiing the red specks ("eye dots") 

 of Euglenee, Rotatoria, the orange-yellow contents of Uredines. They 

 are very contractile, altering their figure on contact as they glide 

 along. Their main direction is centrifxigal, towards the margin of the 

 drop of water in which they are under observation, but they do not 

 always take the shortest coui'se ; they appear also capable of gliding 

 over one another ; some of them thus delayed en route may preserve 

 their original globular figure but having passed the obstacle, upon at 

 fresh start the fusiform figure is reassumed. Sometimes, says the 

 author, a backward motion may take place, ' ' though indeed the final 

 exit from the water appears to be the purpose of this curious wander- 

 ing." As to the cause of the movement, the author knows of no fact 

 capable of leading to an explanation, being of opinion, however, that, 

 " owing to the rigidity of the track, the cause is to be sought in the 

 spindles, though the latter, away from the track, have not the power 

 to move." 



Touching the " tracks " themselves, the author seems to regard 

 them as not differing except in tenuity from the general hyaline basic 

 substance. He was able, by the application of acetic acid, to perceive 

 that the previously seemingly uniform substance now showed a very 

 fine fibrous structure, and pressui'e on the covering-glass enabled him 

 to detach the strings fi'om the central body. When, however, the 

 whole fabric becomes fully evolved under the microscope (that is, the 

 whole "tree" or "labyrinth " developed), it seems to possess no con- 

 tractility, e'V'inces no movement on the surface or in the interior, no 

 projection or retraction of processes or rays comparable to the pseudo- 

 podia of the Rhizopoda : the whole is now a rigid, motionless structure 

 (except, of coiu'se, the wandering spindles). The author would leave 



