TRANSACTIONS OP THE SECTIONS. 127 



and pliysiology. In this country, from social and other considerations, such a divi- 

 sion of labour'is not generally made, but the time will assuredly come when it must 

 be done. 



Histology. 



It may be supposed from these remarks that I regard histology as lying entirely 

 ■wilLin the province of anatomy. By no means. Histology is neutral territory 

 between botli. It is that department of knowledge where tlie two sciences over- 

 lap. The physiologist must investigate minute structure, in which the beginnings 

 oi^pliysiological processes take place, because without Imowledge of it all his ideas 

 as to functions of organs or tissues would be superficial and unsatisfactory. When 

 a physiologist examines a tissue, or a section of an organ, however, the morpholo- 

 gical aspect is not what is prominently before his mind, but its mode of function. 

 To him the form, size, position, and relations of tlie cell are not the special subjects 

 of interest, but its probable mode of action in the economy. He therefore wishes 

 it coidd be seen working, or at all events in conditions as nearly normal as possible. 

 This desire has ab-eady led to the invention of various new methods of research, 

 such as those of the hot stage, or plans for the observations of changes in cells or 

 fibres in parts accessible to the microscope, methods which have already been fruitful 

 of good residts. I have a firm belief that this line of work has by no means been 

 followed to the end, and that along it the physiologist 'will still be conducted to 

 rich harvests in the fields of histological research. 



Methods of Physiolooy. 



The kindred science of physiology has for its object the elucidation of unction, 

 and it has, in addition to the methods of anatomy (namely, dissection, description, 

 and comparison), those of pathological observation and experimentation. It is con- 

 fessedly the science most ditficidt of all to prosecute. The subjects of investiga- 

 tion are intricate in structm-e, and are formed of complex chemical materials, which 

 are in constant interaction with the surrounding world. Each animal is a machine, 

 the intricacies of which are infinitely more involved than those of any human 

 mamrfacture. To stop this machine, in the attempt to discover the action of one 

 of its parts, is a proceeding, in many instances, v/hich interferes with the very part 

 the action of which we wish to find out. As we descend in the scale of animal 

 life, and the machine becomes less complex, this difficidty is not so obtrusive, inas- 

 much as in many animals of simple organization there is not the same dependence 

 of organ upon organ, and of tissue iipon tissue, as we find in the more complex. 

 But in most experimental researches in other sciences the conditions are also mani- 

 fold, and tlie acumen of the philosopher in all is tested in distinguishing the essen- 

 tial from the non-essential conditions. 



In the further prosecution of physiology as a physical science, which it really is, 

 experimental inquirj', with the aid of precise instruments, and the facts derived 

 from the observation of the course and effects of disease, seem to me to be the two 

 lines of evidence which will in future weigh with us in coming to just conclusions. 

 No doubt it is quite true that much of the minute anatomy of the human body, 

 and more so of the minute anatomy of the bodies of the lower animals, is still 

 unknown, and tliat tliere are probably many details, visible only to the microscope, 

 not yet discovered, which may influence our opinions as to the exact functions of 

 parts. This is especially true of the structure of the ncrve-centi'es. Vs'e have at 

 present only very general conceptions of the arrangements of the cells and fibres in 

 these parts, and it is highly probable that future discoveries in this difficidt field of 

 investigation may change our views, not only of nervous action in general, but of 

 the functions of particular centres. Accordingly there can be little doubt that as 

 tlie naked-eye dissection has revealed structural arrangements which have hitherto 

 guided the physiologist to correct notions of function, so in the future a similar 

 service will be done to physiology by the histologist. Still physiology will have to 

 depend less on aid of this nature, and more on the facts obtained by the methods 



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