404 



NATURE 



[August 23, 1894 



whole cell is not of a uniform nature, since there is this on^ 

 point within the cell that exerts a special attraction upon the 

 rest of the cell -substance : and, indeed, on this account the 

 particle has come to be termed the " attraction particle." And 

 in the second place, because of the apparent universality of the 

 occurrence of such a particle. And, thirdly, because of the 

 fact that one of the most important phenomena exhibited by 

 the cell hinges upon the behaviour of this particle ; for it is 

 found that before a cell or its nucleus divides this minute attrac- 

 tion particle begins by itself dividing, and is, in fact, more 

 commonly met with double than single. Nor is it until the 

 two particles thus produced have evolved, either from them- 

 selves or from the substance of the protoplasm or nucleus, a 

 system of communicating fibres, the so-called achromatu spindle, 

 that those changes in the nucleus and protoplasm take place which 

 produce the division and multiplication of the cell. This al- 

 triution particle, which is also called the cenlral particle or centra- 

 some, has absorbed so great an interest thai, short as is its history, 

 many papers have already been devoted mainly to it, the latest 

 of these being an elaborate treatise of some 300 pages by Martin 

 Heidenhain. I shall not here attempt to follow out the details 

 of all these researches, but will be satisfied with putting before 

 you the conclusion which Heidenhain has come to regarding this 

 particle, viz. " that it is morphologically, physiologically, and 

 chemically a %U\xc\.\y!esui generis: not merely a separate portion 

 of nucleus or of protoplasm, but an organ of the cell with 

 definite functions, and having a definite existence of its own.' 

 Nevertheless, it is almost as minute an object as it is possible 

 to conceive. In a cell which is magnified a thousand diameters 

 the central particle appears merely the size of a pin-point. 

 Yet this almost infinitely small object exerts an extra- 

 ordinary influence over the whole cell, however large (and the 

 cell may be many thousand times its size) ; for it initiates and 

 directs those processes which result in the multiplication of the 

 cell, and indirectly, therefore, it is concerned in directing the 

 general growth of the individual, and ultimately the propagation 

 of the species. 



A former President of the Association took as the subject of 

 his presidential address what he was pleased to call the "Next 

 to Nothings." In considering this central particle, of the 

 actual structure of which, and of its chemical constitution, we 

 know at present hardly anything, we may surely regard it as a 

 striking instance of the supreme importance of the " next to 

 nothing " in Physiology. 



The other subjects to which I desire to draw your special 

 attention relate to the physiology of certain organs the functions 

 of which have always been extremely obscure, and which, 

 allhough they differ greatly from one another in almost every 

 point of structure, and presumably also in function, it has been 

 usual to group together under the name of ductless glands. The 

 name "gland" is given to such organs of the body as take 

 materials from the blood, and convey those materials in an 

 altered or unaltered form, by a tube or duct, to a surface either 

 internal or external. Such material is termed the secretion of 

 the gland, and has for its object cither the performing some 

 function which is useful to the organism or the getting rid of 

 material which would be detrimental if retained. In the case 

 of the ductless glands there is no such possibility of pouring out 

 material produced by the gland upon a surface, because these j 

 organs do not communicate with any surface by a duct ; and 

 whatever material they may furnish must therefore, if it is to 

 reach the body generally, pass into the blood ; that is to say, 

 the blood on the one hand must furnish the materials for the 

 secretion of the gland, and on the other hand it must 

 take up those materials after they have been manu- 

 factured into something else, and carry them away to other 

 parts of the l>ody. Now, in the case of a certain number of the 

 ductlcM glands there has not appeared to be any very great 

 obscurity as to their function ; for some of them seem very 

 obviously to be devoted to the formation of corpuscles which 

 are found within the blond itself. Hut with regard to others of 

 these IxKlics it has not hitherto been possible to finil any special 

 material in the blood which ihcy have furnished to it, and our 

 knowledge of them is derived almost entirely from experiments. 

 I will lake the case of two of these to illustrate the vast in- 

 fluence which small and almost disregarded organs may exert 

 upon the whole economy. Hut in the first i)lace I may be per- 

 m"-'i t ■lint out what is indeed asclfevirlent statement, that 

 ' "t of the body which docs not exert some inllucncc 



"1 Every single portion of the body is continually I 



taking materials from the blood, and furnishing to the blood 

 other materials which are formed within it, whether we call that 

 portion which performs such functions a gland or not ; and it is 

 quite certain that the reniov.al of any portion of the body would 

 be followed by some permanent alteration in the blood were it 

 not that other similar parts in.iy by increased activity com- 

 pensate for the .ilterations which the blood would other- 

 wise undergo from the loss of any one such part. Take 

 the case of a limb. The changes which the blood under- 

 goes in circulating through it affect the body generally through 

 that fluid, for the composition of the blood becomes modified 

 in tr.-iversing the limb. And not only is the body aftected thus 

 through the medium of the blood, but, by means of the nerves 

 which pass to and from the limbs, the central nervous system is 

 itself affected by the movements and alterations of various kinds 

 which are proceeding in the muscles and other parts, and through 

 the nervous system the whole organism must constantly be 

 influenced from the limb. There is, however, no evidence that 

 the removal of a limb or part of a limb permanently modifies 

 e;lher the condition of the blood or of the nervous system. Xor 

 is such a result to be expected, for in thi< case there are other 

 parts of the body possessing similar organs and performing 

 similar functions, the increased activity of which may e.isily 

 compensate for the loss which is sustained through removal of 

 such a part. 



Hut if we deal with an organ which is not multiple, but 

 unique, and completely remove this from the body, it is easy to 

 see that the case may be very dift'erent. This organ, like every 

 other organ of the body, is continually taking from the blood some 

 materials and giving up to it certain other materials. Now 

 it is clear that its removal must make a permanent difference in 

 the blood, and since the whole organism is remarkably sensitive 

 to even slight changes in the composition of the circulating 

 fluid, very marked results may well follow the removal of such 

 organ. And this is in fact found experimentally to be the case. 



It has long been known that extensive disease of the thyroid 

 gland, a small reddish organ, weighing about one or two 

 ounces, found at the front of the throat, is followed by exten- 

 sive alterations in the nutrition of the body generally. The 

 patient becomes swollen from the overloading of the connective 

 tissues with a mucinous exudation ; the nervous and muscuLar 

 systems are seriously affected ; the power of generating heat is 

 greatly modified ; and the final result is, in the first instance, 

 the proluctionof a condition of semi-idiocy, ultimately followed, 

 if the disease be extensive, by death, Precisely similar results 

 have been founii in animals, and in fact in man as well, to 

 follow the complete removal of this body. Yet the weight of 

 this organ is not more than one sixteen-hundredth part of 

 the whole weight of the body ; .ind even this figure does not re- 

 present the enormous influence which a relatively small organ 

 can exert upon the general nutrition of the body ; for it is 

 found that even if a minute part of the thyroid gland be left 

 whilst the greater part is removed, the symptoms above 

 enumer.ited do not supervene. Indeed, certain contradictory 

 results which have been got by some observers after removal of 

 the thyroid are explained by the fact that in some individuals 

 there are minute detached particles of thyroid gland lying ap.irl 

 from the main organ ; and that after the latter has been re- 

 moved these detached particles may sulliciently carry on the 

 function of the organ in relation to the blood and the nervous 

 system to prevent the supervention of the deleterious symptoms 

 which usually occur after its removal. Here is, then, a notable 

 instance of the enormous influence exerted by a "next to 

 nothing" upon the general organism. 



Another illustration may be given from these ductless glands. 

 It was noticed in 1S49 by a celebrated physician. Dr. Addison 

 of Guy's Hospital, that certain cases, accompanied by extreme 

 debility, occurring in the human subject were .issociated with 

 the appearance of peculiar bronzed patches on parts of the 

 skin and mucous membranes ; and on post-mortem examina- 

 tion of these cases, which always sooner or Later have a fatal 

 termination — and indeed sooner rather than later — he fi)und the 

 symptoms in question to be accompanied by disease and destruc- 

 tion of the suprarenal capsules — small bodies which are placed 

 close to the kidneys, but which, so far as we know, have no 

 physiological connection with them. Now when experiments 

 came to be directed upon these bodies in order to elucidate 

 their functions, and especially to abscrve whether their injury or 

 removal was accompanied in animals also by symptoms similar 

 to those occurring in man as the result of disease, it was found 



NO. 1295. VOL. 50] 



