SMALL MASSES OF ZCK)GL(EA 195 



one of them has been seen to divide." In some ordinary hay 

 infusions also, Amoebse are produced in great numbers from the 

 discrete corpuscles. A number of small and large Amoebae that 

 were found with multitudes of others on the surface of a rather 

 old pellicle, in which they had had time to grow, are shown in 

 Fig. 26, C (x 500) ; while B represents other Amcebze beginning to 

 encyst in another hay pellicle on the twelfth day, the upper one of 

 which still exhibited very sluggish movements ; and D ( X 500) 

 shows many others completely encysted, in which the protoplasm 

 is, in some of them, more or less contracted, and shrunk away from 

 the cyst-wall. 



An infusion of roses made from the flowers, leaves and stems, or 

 even from the petals only, often yields Amcebse in great abundance. 

 In making an infusion from the latter, the petals were allowed to 

 macerate for about twelve hours before the fluid was filtered off. 

 The Amoebas found in such infusions are sometimes very short- 

 lived. Thus, in one of them they were very abundant and active 

 on the fourth day, but two days later they were almost all found 

 to have become encysted. 



The production of Amoebae in abundance is again practically 

 invariable in mixtures of egg and water. When one tea-spoonful of 

 mixed white and yolk of an egg is added to eight ounces of filtered 

 water, enormous quantities of Amoebas are to be found, after a time, 

 in the pellicle which forms on such a mixture, though they have 

 generally been preceded by the appearance of Monads. A very 

 thick and glistening pellicle is commonly produced, and after six 

 or seven days Amcebje appear therein in great abundance. Their 

 presence may be rendered most obvious by allowing portions of 

 the pellicle to soak in a drop or two of logwood solution for some 

 hours. Their actual mode of origin is apt to escape observation 

 owing to the thickness of the pellicle in which they are formed. 

 Still, on a few occasions, I have been fortunate enough to find 

 very cogent evidence that they are formed in just the same way 

 that the discrete corpuscles are produced from the pellicles on hay 

 infusions — that is, by individualisation and metamorphosis of minute 

 portions of Zoogloea. 



As these discrete corpuscles sometimes develop into Monads and 

 sometimes into Amoebae, I have been accustomed to speak of them 

 as "indifferent corpuscles." Not unfrequently, however, after 

 their formation, they may remain for a long time quiescent and 

 without developing in either direction. This was the case in a hay 



