202 Proceedings of the Royal Physical Society. 



however, certain organic substances, which usually cause 

 small appreciable chemical change in the tissues, such as the 

 poisonous alkaloids and albumenoids, and which, as poisons, 

 seem to produce very different results on different kinds of 

 living tissue. Plants which owe their poisonous properties 

 to these alkaloids, generally contain them disseminated 

 throughout all their organs, and in some cases are apparently 

 immune to their effects as poisons. Some of the lowest 

 forms of life appear to live with impunity in media saturated 

 with poisonous albumenoids. Small doses of these poisonous 

 substances have very marked effects upon the higher animal 

 life, and though they often cause death among the lower 

 forms of tissue, their poisonous property seems to be chiefly 

 directed towards the nervous and muscular systems. Their 

 effects as convulsants or narcotics upon these tissues would 

 appear to have some relation to their power of altering in 

 kind or degree the form of katabolism which the tissues 

 normally undergo. Looked at from the point of view of 

 stability or instability of the products of anabolism, the 

 animal tissues, and especially those whose kind of katabolism 

 is the most highly governable and elaborate, are just those 

 on which we would expect these substances to act most 

 powerfully, if we consider the governability of the katabolism 

 to depend directly upon the elaboration and instability of 

 the products of anabolism. Should this be so, we might infer 

 that the presence of katastates in animals tends to produce 

 a further instability of the protoplasm, or to alter it in some 

 way so as to completely stop its action, their first effect being 

 to act as excitants, but in larger doses to so alter the in- 

 stability as to act as convulsants or narcotics. The poisonous 

 nature of the waste products in animals is well shown by 

 the increasing complexity of the systems for the excretion of 

 these substances. Plants, when looked at from the point of 

 view of greater stability in the products of their anabolism, 

 would, by the presence of these substances, have their 

 protoplasm rendered more irritable and unstable, and this 

 would favour the retention of a generalised condition. The 

 Fungi, which appear almost always to live in a close associa- 

 tion with these substances, might owe their degenerate 



