TRANSACTIONS OF SECTION I. 775 



Amoeboid movement, ciliary movement, the contraction of muscle, cell division, 

 and karyokinesis all fall into the same category as being mainly dependent on the 

 stimulating action of ions. 



Loeb has even gone so far as to consider that the process of fertilisation is 

 mainly ionic action ; he denies that the nuclein of the male cell is essential, but 

 asserts that all it does is to act as the stimulus in the due adjustment of the pro- 

 portions of the surrounding ions, and supports this view by numerous experiments 

 on ova in which without the presence of spermatozoa he has produced larvae by 

 merely altering the saline constituents and so the osmotic pressure of the fluid 

 that surrounds them. Whether such a sweeping and almost revolutionary notion 

 will stand the test of further verification must be left to the future; so also 

 must the equally important idea that nervous impulses are to be mainly explained 

 on an electrolytic basis. But whether or not all the details of such work will 

 stand the test of time, the experiments I have briefly alluded to are sufficient 

 to show the importance of physical chemistry to the physiologist, and they also 

 form a useful commentary on what I was saying just now about vitalism. Such 

 eminently vital phenomena as movement and fertilisation are to be explained in 

 whole or in part as due to the physical action of inorganic substances. Are not 

 such suggestions indications of the undesirability of postulating the existence of 

 any special mystic vital force ? 



I have spoken up to this point of physical chemistry as a branch of inorganic 

 chemistry; there are already indications of its importance also in relation to 

 organic chemistry. Many eminent chemists consider that the future advance of 

 organic chemistry will be on the new physical lines. It is impossible to forecast 

 where this will lead us ; suffice it to say that not only physiology, but also 

 pathology, pharmacology, and even therapeutics, will receive new accessions to 

 knowledge the importance of which will be enormous. 



I have now briefly sketched what appear to me to be the two main features of 

 the chemical physiology of to-day, and the two lines, organic and inorganic, along 

 which I believe it will progress ia the future. 



Let me now press upon you the importance in physiology, as in all experimental 

 sciences, of the necessity first of bold experimentation, and secondly of bold 

 theorising from experimental data. Without experiment all theorising is futile ; 

 the discovery of gravitation would never have seen the light if laborious years of 

 work had not convinced Isewton that it could be deduced from his observations. 

 The Darwinian theory was similarly based upon data, and experiments which 

 occupied the greater part of its author's lifetime to collect and perform. Pasteur 

 in France and Virchow in Germany supply other instances of the same devotion 

 to work which was followed by the promulgation of wide-sweeping generalisations. 



And after all it is the general law which is the main object of research ; 

 isolated facts may be interesting and are often of value, but it is not until facts 

 are correlated and the discoverers ascertain their interrelationsbips that anything 

 of epoch-making importance is given to the world. 



It is, however, frequently the case that a thinker with keen insight can see the 

 general law even before tbe facts upon which it rests are fully worked out. Often 

 6uch bold theorisers are right, but even if they ultimately turn out to be wrong, 

 or only partly right, they have given to their fellows some general idea on which 

 to work ; if the general idea is incorrect, it is important to prove it to be so in 

 order to discover what is right later on. No one has ever seen an atom or a 

 molecule, yet who can doubt that the atomic theory is the sheet anchor ot 

 chemistry ? Mendeleetf formulated his periodic law before many of the elements 

 were discovered ; yet the accuracy of this great generalisation has been such that 

 it has actually led to the discovery of some of the missing elements. 



I purpose to illustrate these general remarks by a brief allusion to two typical 

 sets of researches carried out during recent j'ears in the region of chemical physio- 

 logy. I do not pretend that either of them has the same overwhelming import- 

 ance as the great discoveries I have alluded to, but I am inclined to think that one 

 of them comes very near to that standard. The investigations in question are 

 those of Ehrlicb and of Pawlow. The work of Ehrlich mainly illustrates the useful 



