July 6, 1876] 



NATURE 



215 



during contraction, and it furnishes results identical to those 

 obtained by investigating the shortening of the muscle during 

 contraction in living animals. We are then quite authorised to 

 interpret in the same way the curves obtained in both cases. 



It is needless to insist on the numerous services which the myo- 

 graphy of man may render to physiology and medicine. The 

 study of the forms of movement, of the latent period, of muscle, 

 and perhaps even the rate of transmission of impulses along 

 motor nerves, by means of this apparatus may be as easily pur- 

 sued in healthy or unhealthy men as in animals. 



2. Without quitting the investigation of muscular movements, 

 let us examine that ot the respiratory movements, and we shall 

 obtain valuable information as to the means by which the im- 

 portant function of respiration is effected. We apply to the 

 chest this apparatus formed of an elastic plate and furnished 

 with two lever arms, to the extremity of which is attached a 

 band which surrounds the thorax. Each dilatation of the chest 

 causes the spring to bend, and it resumes its position during res- 

 piration. This double movement is accompanied by a rising and 

 falling of the membrane of the drum which forms part of the 

 apparatus, and which therefore becomes a regular bellows, 

 causmg the elevation and depression of the inscribing lever 

 placed beside the cylinder. 



The respiratory curves thus obtained present certain normal 

 characteristics susceptible of being greatly modified when any 

 obstruction interferes with the respiratory functions either by 

 impeding the entrance or the exit of the ait, or even by opposing 

 its passage in both directions. In all these cases the curves have 

 a special physiognomy, and their simple inspection enables us to 

 recognise the seat of the obstacle to respiration. Clinical research 

 will yet discover here many points for investigation. 



3. But above all there are the phenomena of circulation, which 

 have been minutely investigated both in man and animals. The 

 apparatus by means of which we can completely analyse the 

 movement of the heart, the arterial pulse, &c., have already 

 rendered great service ; we are, however, right in expecting 

 yet more from it, by making use of it in clinical investigations. 



Of various cardiographs, that on which I wish to dwell differs 

 little from the explorer of which I have already spoken. The 

 knob with which it is provided is applied to the region of the 

 apex of the heart, and each beat of the organ is transmitted to 

 the recordmg lever. There is seen in this pulsation of the heart 

 the same elements which the physiological cardiograph has re- 

 vealed in the higher animals. This beating of the heart is then 

 a complex act, and the numerous details which have been dis- 

 covered by graphic analysis have each a considerable importance 

 from the point oT view of functional investigation. One part of 

 the tracing shows us how the ventricle is emptied into the artery ; 

 another enables us to appreciate the play of the auricle, the 

 beating of the sigmoid valves, &c. You will easily see that the 

 precise diagnosis of affections of the heart, already carried so 

 far, thanks to auscultation, will be greatly improved by the 

 application to man of the cardiograpti applied to the study of 

 the pulsation of the heart 



The arterial pulse cannot be separated from the pulsation of 

 the heart in the study of the phenomena of circulation in man. 

 Already numerous researches have been undertaken by means of 

 the direct sphygmograph ; but much more may be expected from 

 the use of the air sphygmograph {sphygmographe d, transmission). 



I place this apparatus upon my wrist, and the artery raising a 

 spring connected with the membrane of the exploring drum, 

 transmits its movement to a distance by means of the tube filled 

 with air, which enables this sphygmograph to communicate with 

 the dram to which the recording lever is attached. By record- 

 ing simultaneously the traces of the pulse and those of the 

 heart much information may be obtained and many errors 

 avoided. 



4. I shall present to you, in conclusion, a new method of 

 investigating the peripheral circulation. This method is based 

 on the principle that the variation of the calibre of the blood- 

 vessels in any part of the body is faithfully indicated by the varia- 

 tions of the volume 01 that part. Without dwelling on the history 

 of these investigations, I may tell you that they originated many 

 years ago. Dr. Piegu, of Paris, having pointed out in 1846 the alter- 

 nate expansion and contraction of the tissues in connection with 

 the dilatation and contraction of the blood-vessels. Since that 

 time Chelius and Fick in Germany, Mosso in Italy, Franck at 

 Paris, have carried on and extended these researches. 



The recording of the movements of a column of water inclosed 

 in a tube communicating with a receiver filled with water and 

 into which the hand and forearm is plunged^ was first eifecied 



by Fick by means of a float armed with a pen. Ch. Buisson 

 hit on the happy idea of transmitting to a distance, by means of 

 tubes filled with air, the oscillation of the column of water, 

 and it is with his apparatus that M. Franck, in my laboratory, 

 has executed a series of researches. You see the apparatus in 

 action. The hand is plunged into this jar filled with water and 

 hermetically closed. A vertical tube, furnished with a bulb to 

 avoid the effects of the speed acquired by the liquid, serves to 

 transmit to a recording lever the oscillation of the column of 

 water. You will remark that these oscillations are rhythmical 

 with the heart, and if we record them by the side of the cardiac 

 pulse registered by the transmitting sphygmograph, we can 

 establish the identity of the variations in size or, as we may term 

 them, the pulsations of the hand and of the pulsations of a single 

 artery. With this apparatus we may perform numerous experi- 

 ments on the mechanical effects of compression of the arteiies 

 or veins, the action of the vaso-motor system of nerves, direct or 

 reflex, &c. 



I shall not explain to you by the side of this method of investi- 

 gation, that which we owe to Mosso, of Turin. His plsthysmo- 

 graph, which ought soon to be presented to you, permits the 

 estimation of changes of volume of the hand, and, assiaredly, the 

 combination of these two processes ought to lead to important 

 results in the investigation of the phenomena of peripheral circii- 

 lation. 



I have sought to submit to you some of the points more 

 immediately applicable to man, without dwelling on the investi- 

 gation of the movements among animals. But these two orders 

 of researches complement eacii other. We may say that most 

 of the data furnished by experimentation on animals are now 

 susceptible of rigorous verification on man, healthy or unhealthy. 

 This verification we owe to investigation by means of precise 

 apparatus and to the recording of the smallest movements, thanks 

 to the registering instruments, the principal specimens of which 

 are sho ^n in this Collection. 



DREDGINGS OF THE " CHALLENGER", 



pROF. WYVILLE THOMSON had not set foot long in Old 

 ■^ England before presenting in person a preliminary quota 

 of his results to the learned bodies. Two papers read by him at 

 the Linnean Society on June i, embodied observations on 

 Echinodermata, a group to which, as is well known, he pre- 

 viously had paid much attention. One of the communications 

 described some new living Crinoids belonging to the Apio- 

 crinidse. Of deep-sea forms the stalked crinoids are extremely 

 rare, and have a special interest on account of their palseon- 

 tological relations ; it was therefore with satisfaction that neat" 

 St. Paul's rocks at 1,850 fathoms, the trawl brought up, among 

 other things, an entire specimen of a new crinoid, Bathycrinus 

 Aldrichianus, and fragments of another, Hyocrinus bethellianus. 

 At other stations and on different occasions, were obtained an- 

 other species of Bathycrinus {B. gracilis) and an undetermined 

 beautifid little species of Hyocrinus, besides examples of the 

 Rhizocrinus lofotensis of Sars ; all of these being referable to the 

 Apiocrinidae. In pointing out their structural peculiarities and 

 alluding to Bathycrinus, he mentioned that the stem barely 

 enlarges at its junction with the cup, the ring formed by the 

 basals is very small, and the first radials are free from the basals 

 and often free from one another, while the oral plates are absent. 

 This genus appears to possess an assemblage of characters in 

 some respects intermediate between Rhizocrinus and the pen- 

 tacrinoid stage of An'.edon. Hyocrinus bethelltanus has much 

 the appearance, and in some prominent particulars it s6ems to 

 have very much the structure of the palaeozoic genus Platycrinus 

 or its sub-genus Dichocrinus, The stem is much more rigid than 

 that of Bathycrinus ; the cttp consists of two tiers of plates only, 

 the lower is to be regarded as a ring of basals, and the upper 

 consists of fine spade-shaped radials. There are five arms wbich 

 are pinnulated. The proximal pinnules are very long, running 

 on nearly to the end of the arm, and the succeeding pm- 

 nules are gradually shorter, all of them, however, running out 

 to the end of the arm. Distally the ends of the tive arms, and 

 the ends of all the pinnules meet nearly on a level. Thij 

 arrangement is unknown in recent crinoids, although we have 

 something close to it in species of the fossil genera Pottriocrinus 

 and Cyathocrinus ; with this, however, their resemblances end. 

 Rhizocrinus finds its ally in the cretaceous genus Bourgueiicrinus ; 

 Bathycrinus and Hyocrinus are evidently related to the former, 

 but the characters of the Apiocrinidae are nevertheless obscure in 



