Sachs' Lectures. 
85 
radically different origins. This proceeding, to which he apparently 
attaches some importance, seems to us to involve the sacrifice of a 
useful word on the altar of uniformity. Words of everyday use 
are, it is true, often used in science in the manner advocated by 
Professor Sachs ; thus we speak of the wings of insects, or the 
legs of a caterpillar. But many familiar words are used, morpho- 
logically, as is the case with the word ‘ wrist ’ in this sen- 
tence : ‘ a horse’s knee is a wrist/ This is surely a convenient 
usage to which we may conform with advantage. Again, when we say 
* an underground stem is not a root/ we use the word root in a 
morphological sense, and the meaning is clear. But if the mycelium 
of a mould is to be called a root, as Professor Sachs suggests, and 
generally speaking if we are to cease to use the names of organs 
morphologically, we shall soon fall into difficulties. Professor Sachs 
goes on (p. 6) to consider the forms which diverge from the type, 
under the headings, rudimentary ^ , reduced , and metamorphosed or 
derived organs. This last category contains such organs as the 
tendril of the vine, which it is ‘ against common sense ’ to consider as 
degenerate. Here again we confess that Sachs’s ideal physiological 
types do not seem well adapted for the treatment of the question. 
These types are in fact generalisations of the adaptations of plants to 
the conditions of life. The idea of the shoot-^nd-root-ty^Q is derived 
from the fact that plants are as a rule adapted both for life within and 
life without the substratum. The generalisation is interesting, but it 
seems to us more in place in the study of the environments, than in 
the study of the organism and its derived forms. Take such a case of 
metamorphosis as that presented by root-like water-leaves of Salvinia ; 
surely the treatment of such a case is simpler if we adhere to the 
ordinary morphological point of view, than if we adopt Professor 
Sachs’s standpoint. According to this latter view indeed, we presume 
that the water-leaves would be called roots if it were not for the fact 
that the reproductive organs are developed in them — and this seems 
hardly the criterion which ought to decide such a case. Fortunately 
however (if we may say so without disrespect) Professor Sachs does 
not adhere with absolute strictness to his own plan. Thus in speaking 
of the haustoria of Cuscuta he says (p. 27), ‘That these latter [the 
1 Rudimentary is here used in the classically correct sense of a first attempt ; 
such organs are usually known in English by the term nascent , while Sachs’s 
reduced organs are called rudimentary . 
