272 DESIGN IN NATURE 



cutting, and dividing muscles and nerves and other structures wholesale is never wholly satisfactory. Similarly, 

 the recording of movements, normal and abnormal, by comphcated registering apparatus is liable to error. To 

 get quite natural results animals must be studied in their entirety and in their natural condition, and the changes 

 and movements occurring in them recorded, if possible, by instantaneous photography. The simpler animals yield 

 the best results, and amongst them the transparent and semi-transparent animals are the most satisfactory. To 

 obtain normal results, animals must be studied imder normal conditions. The extensive mutilation of highly 

 complex, highly sensitive animals, and the registration of movements so produced by graphic methods, have intro- 

 duced many serious errors into physiology. The methods employed are, everything considered, extremely crude, 

 and the results obtained are, with few exceptions, equally disappointing and misleading. The time, it appears to 

 me, has now arrived for seriously questioning the doings of the mechanical school of physiology. 



§ 54. Respiratory Rhythmic Movements in Animals— New Explanation of these Movements. 



The observations on rhythmic muscles made in the last section (§ 53) will prepare the reader for what has now 

 to be said regarding the respiratory movements in plants and animals, especially the latter. 



The respiratory rhythmic movements in animals are tj'pical of their kind, and in some respects the most 

 important in the body. They begin as soon as the act of parturition is completed and continue as long as life 

 lasts. Any interruption to them for more than a few minutes is almost invariably fatal. 



They are vital, fundamental, involuntary, co-ordinated movements — that is, they form part of a living system 

 which, if interfered with to any extent, results in death. 



The other great organic rhythms are those of aUmentation, the circulation, reproduction, &c. 



These rhythms are coeval with hfe. The structures which produce them are specially formed during the 

 development and growth of the individual — they are designed and prepared beforehand, and the work to be per- 

 formed by them is taken up when the proper time arrives. In plants, the fundamental rhythmic movements are 

 carried on in the absence of both muscles and nerves, and it is important to bear this in mind, as one is apt to 

 imagine that muscles and nerves are necessary to the production of rhythmic movements. When muscles and 

 nerves are present the rhythms inhere in the muscles rather than in the nerves and nerve centres ; the nerves in 

 the higher animals being necessary to co-ordinate the several systems of rhythms in the several individuals. They 

 cannot be said to occasion them. The nerves, within hmits, quicken or slow the rhythms, but that is the most that 

 can be said.^ 



The nerves exercise an influence on the nutrition of the structures in which the rhythms occur. But when all 

 has been said, rhythms in plants and animals are fundamental. They occur, as already stated, in the absence of 

 and as apart from nerves. They are not even referable to nutrition, as the rhythmic structures of plants and animals 

 are not known to feed at certain intervals. 



Rhythms in the higher animals are bound up with life, inasmuch as the cessation of any one of the more 

 important of them involves the death of the individual. 



They are fundamental, because they are provided for in the constitution and substance of the individual. 



The rhythms afford examples of co-ordinated movements, as they are produced by the consentaneous action 

 of a great many parts, and, in the higher animals, by a great many muscular fibres or muscles running in various 

 directions and, in some cases, arranged in several planes. This is especially true of the heart and of the muscles 

 of respiration, where the diaphragm, the thoracic, abdominal, and other muscles are involved. They are involuntary 

 because in the higher animals and in ourselves they go on day and night, waking and sleeping, from the cradle to 

 the grave, without effort on our part. They cannot be controlled (unless for a very brief period) by even the strongest- 

 willed and most resolute individuals. A time comes, and comes quickly, when, if the respiratory movements are 

 suppressed, the want of breath becomes intolerable. 



An interesting comparison may be drawn as between the cardiac and respiratory muscles in man. The only 

 point in which the muscular arrangements of the ventricles of the heart differ from those of the chest, abdomen, 

 and diaphragm, is that the muscles of the latter are attached to bones : those of the former having no such 

 attachments and being continuous upon themselves. This really makes no difference ; the opening and closing 

 movements of the heart, chest, &c., being essentially the same. 



The chest may be hkened to the systematic heart of the mammal, which consists of an auricle and ventricle 



1 It is not usual to speak of a rhythmic action in nerves, but there are several circumstances whicli favour this view. Division of the inferior 



V \ ■ 1; —'^ "" ...^i. ......i.o.,„ ui iiijuui.iii.; auuiuii. ijiB ongin or rnyDnms, wnicn 1 regara as vital ana tunaaraental m the lowest ulant nnrl in 



the highest animal, is, however, not satisfactorily explained liy this hypothesis. On the whole I incline to the opinion that rhythms ai-p Ltt^^^l 



I'ves exist. 



tire Highest animal, is, however, not satisfactorily explained hy this hypothesis. On the whole I incline to the opinion that rhythms are inhp t 

 m living matter— plant and animal- as apart from nerves. Rhythms certainly occur in plants and in structures where no nerves exist 



