T KANSACTIONS OV THK SKCTIONS. 75 



known researches of Mr. Lockliart Clarke on the nervous centres, which, I am 

 liappy to say, he continues successfully to prosecute, — the discoveries of Professor 

 Beale on the structui-e of ganglions and of nerve-fibres, and their ultimate distri- 

 bution in the tissues and organs, — and the interesting observations of JMi-. Hulke 

 on the retina. By usmg high microscopic powers, with the greatest address and 

 skill, Dr. Beale found out exquisitely minute fibrils in the peripheral branches of 

 the nerves, and traced their distribution in various tissues. These inquiries have 

 been followed up by the German histologists, and now it is maintained that nerve- 

 fibres may be traced even into the particles of epithelium. Be this as it may, it is 

 satisfactory to know that, as the functional influence of the nerves has been found 

 to govern in a higher degree and more dii-ect manner than formerly suspected the 

 circulating, secreting, and other nutritive processes, so om- knowledge of the 

 anatomical domain of the nervous system is being correspondingly extended. As 

 a marked instance, I may refer to the recent observations on the termination of 

 nerves in the secreting epithelium of glands. In proceeding to say a word on 

 other instrumental applications, I may pass over the continued investigations into 

 the electricity of nerves and muscles, and new determinations, by new methods, 

 of the velocity of nervous^excitation, as well as new observations with the ophthal- 

 mometer, ophthalmoscope, laryngoscope, and the newly invented cardiogTaph, and 

 shall content mj^self with specializing the investigations made in this country 

 into the phenoruena of the pulse, in health and disease, by means of the spbygmo- 

 graph, and the important experimental inquiries of Dr. Sanderson on the influence 

 of the thoracic movements on the circulation of the blood, carried on by means of 

 the hasmadynamometer and additional ingenious apparatus contrived by himself. 

 The accoimt of his observations is contained in the Croonian Lecture for 1866, 

 delivered by him before the Eoyal Societ}', which will shortly be published in the 

 Philosophical Transactions. An important contribution to the physiology of 

 respiration was, not long since, derived from a combined chemical and optical 

 investigation, by Professor Stokes, into the oxidation and deoxidation of the 

 colom-ing-matter of the blood. Spectnmi analysis promises much aid in physio- 

 logical inquiry. It has been already employed )jy Dr. Bence Jones and JIi-. Dupre, 

 in a most remarkable and extensive series of experiments on the time required for 

 the absorption and elimination of foreign matters by the living tissues. The sub- 

 stance used was a salt of lithia, and it was traced into and out of the non-vascidar 

 as well as the vascular tissues. The continued employment of chemical means in 

 physiological inquiries scarcely requires any comment. I must nevertheless make 

 an exception in regard to some recent experimental residts which lead to an impor- 

 tant modification of the views heretofore generally entertained as to the generation 

 of muscular force. From an experiment, now well known, by Fick and Wislicenus, 

 in an ascent of the Faulhom, these observers concluded that the mechanical force 

 and heat developed in muscular exertion cannot be derived solely or principally 

 from oxidation of the proper muscular tissue. Dr. Fraukland has subjected their 

 data and conclusions to a careful chemical criticism, in which he determined ex- 

 perimeutallv the heat,_ and consequently the mechanical force, produced by the 

 oxidation of albuminoid substances ; and, on comparing this with the results of 

 the Alpine experiment, he has fuUy confirmed the conclusions drawn from it. It 

 would therefore seem as if a muscle ordinarily uses other materials, probably 

 hydrocarbonous, to be oxidated in the production of force, as a steam-engine uses 

 fuel, and not its own substance. More lately Professor Parkes has made, at the 

 Netley Hospital, two series of very careful experiments, in which the whole of the 

 discharged nitrogen was exactly determined; and his experiments, which are 

 related m two recent Numbers of the ^Proceedings of the Koyal Society,' lead to 

 the same general inference as those of the Swiss inquirers ; 'but Dr. Parkes has 

 further found that nitrogen is retained dm-mg the actual performance of work, 

 perhaps even taken up in some form by the muscle and assimilated, and that the 

 discharge of it mainly takes place in the period of rest which succeeds exertion. 

 Without undidy protracting these rather desultory remarks, I may be permitted 

 to speak of a new and curious method of researcli quite recently introduced by a 

 foreign experimenter, which has as yet been especially employed for tracing the 

 more intimate distribution of the ducts in the liver "and kidney, but is possibly 



