AN AQUATIC MYXOMYCETE. 79 



always make their appearance from spores, &c., introduced with those 

 of the culture; but, as already said, it is not difficult to exclude 

 Infusoria and other relatively large oxygen-consumers, and the myxa- 

 mcebse seem to nourish so well in the presence of a certain quantity of 

 bacteria, that the question naturally suggests itself whether the latter 

 do not favour their growth and nutrition, either by breaking up the 

 organic matter, or by serving directly as food. This point is not easy 

 to decide : in cases where the myxamcebse pass over rapidly into a 

 dormant condition in a solution of nutritive substances, it is difficult 

 to determine whether a want of oxygen (due to the long-continued 

 boiling, &c.) or some other cause is acting, and any manipulation 

 introduces risks which only increase the final difficulty. 



For instance, having satisfied myself that something other than pure 

 water and minerals was absolutely necessary for the nutrition of the 

 myxamcebse, the next question was, is organic matter (derived from 

 boiled Hyacinth roots, e.g.) in solution the only other ingredient neces- 

 sary 1 and in the successful cultures one always felt that the answer 

 was obscured because there were always bacteria present, and three 

 obvious possibilities suggested themselves : (1) the myxamcebse might be 

 feeding simply and directly on the dissolved substances in the original 

 solution ; (2) they might be absorbing substances that only arose after 

 the action of the bacteria on the original solution ; and (3) they might 

 be chiefly nourished by the bacteria themselves, since they certainly 

 envelope bacteria after the usual manner of amoebae. It thus follows 

 that my experiments only prove that organic matter in some form is 

 necessary for the nutrition and growth of the myxamcebse, but do not 

 decide in what form it is absorbed. I regard the last question as 

 important with respect to any hypothesis as to the animal or vegetable 

 characteristics of the amoeboid stage, though a positive answer even to 

 this question could by no means be regarded as conclusive of the 

 animal nature of the organism, in view of the other facts to hand. 

 It may be shortly remarked, in this connection, that the conditions 

 of cultivation in my damp-cells must have been remarkably similar 

 to those which the myxamcebse meet with in the roots on the glass 

 vessels. I may now pass on to the other phenomena observed in the 

 life of the myxamcebse. 



