METAMORPHOSIS OF TISSUES. 



43 



According to the first formula, carbon and 



f hydrogen have been separated; according 

 to the two last, a certain proportion of all 

 the elements has been removed 

 19. We must admit, as the most im- 

 portant result of the study of the composi- 

 tion of gelatinous tissue, and as a point un- 

 deniably established, that, although formed 

 front compounds of proteine, it no longer 

 belongs to the series of the compounds of 

 proteine. Its chemical characters and com- 

 position justify this conclusion. 



No fact is as yet opposed to the law, de- 

 duced from observation, that nature has ex- 

 clusive-ly destined compounds of proteine 

 for the production of blood. 



No substance analogous to the tissues 

 yielding gelatine is found in vegetables. 

 The gelatinous substance is not a compound 

 of proteine ; it contains no sulphur, no phos- 

 phorus, and it contains more nitrogen or less 

 carbon than proteine. The compounds of 

 proteine, under the influence of the vital 

 energy of the organs which form the blood, 

 assume a new form, but are not altered 

 in composition; while these organs, as far as 

 our experience reaches, do not possess the 

 power of producing compounds of proteine, 

 by virtue of any influence, out of substances 

 which contain no proteine. Animals which 

 are fed exclusively with gelatine, the most 

 highly nitrogenized element of the food of 

 carnivora, died with the symptoms of starva- 

 tion ; in short, the gelatinous tissues are 

 incapable of conversion into blood. 



But there is no doubt that these tissues 

 are formed from the constituents of the 

 blood ; and we can hardly avoid entertain- 

 ing the supposition, that the fibrine of venous 

 blood, in becoming arterial fibrine, passes 

 through the first stage of conversion into 

 gelatinous tissue. We cannot, with much 

 probability, ascribe to membranes and ten- 

 dons the power of farming themselves out 

 of matters brought by the blood ; for how 

 could any matter become a portion of the 

 cellular tissue, for example, by virtue of a 

 force which has as yet no organ ? An al- 

 ready existing cell may possess the power of 

 reproducing or of multiplying itself, but in 

 both cases the presence of a substance iden- 

 tical in composition with cellular tissue is 

 essential. Such matters are formed in the 

 organism, and nothing can be better fitted 

 for thpir production than the substance of 

 he cells and membranes which exist in ani- 

 mal food, and become soluble in the stomach 

 during digestion, or which are taken by man 

 in a soluble form. 



20. In the following pages I offer to the 

 reader an attempt to develope analytically 

 the principal metamorphoses which occur 

 in the animal body; and, to preclude all 

 misapprehension, I do this with a distinct 

 protest against all conclusions and deduc- 

 tions which may now or at any subsequent 

 period be derived from it in opposition to 

 the views developed in the preceding part 

 01 this work, with which it has no manner 



of connexion. The results here to be de- 

 scribed have surprised me no less than they 

 will others, and have excited in my mind 

 I the same doubts as others will conceive; 

 | but they are not the creations of fancy, and 

 I give them because I entertain the deep 

 conviction that the method which has led to 

 them is the only one by which we can hope 

 j to acquire insight into the nature of the 

 organic processes. 



The numberless qualitative investigations 

 of animal matters which are made are 

 equally worthless for physiology and for 

 chemistry, so long as they are not instituted 

 with a well defined object, or to answer a 

 question clearly put. 



If we take the letters of a sentence which 

 we wish to decipher, and place them in a 

 line, we advance not a step towards the dis- 

 covery of their meaning. To resolve an 

 enigma, we must have a perfectly clear con- 

 ception of the problem. There are many 

 ways to the highest pinnacle of a mountain ; 

 but those only can hope to reach it who 

 keep the summit constantly in view. All 

 our labour and all our efforts, if we strive to 

 attain it through a morass, only serve to 

 cover us more completely with mud; our 

 progress is impeded by difficulties of our own 

 creation, and at last even the greatest strength 

 must give way when so absurdly wasted. 



21. If it be true that all parts of the body 

 are formed and developed from the blood or 

 the constituents of the blood, that the exist- 

 ing organs at every moment of life are trans- 

 formed into new compounds under the in- 

 fluence of the oxygen introduced in the 

 blood, then the animal secretions must of 

 necessity contain the products of the meta- 

 morphosis of the tissues. 



22. If it be further true, that the urine 

 contains those products of metamorphosis 

 which contain the most nitrogen, and the 

 bile those which are richest in carbon, from 

 all the tissues which in the vital process have 

 been transformed into unorganized com 

 pounds, it is clear that the elements of the 

 bile and of the urine sdded together, must 

 be equal in the relative proportion of these 

 elements to the composition of the blood. 



23. The organs are formed from the blood, 

 and contain the elements of the blood ; they 

 become transformed into new compounds, 

 with the addition only of oxygen and of . 

 water. Hence the relative proportion of; 

 carbon and nitrogen must be the same as in 

 the blood. 



If theri we subtract from the composition 

 of blood the elements of the urine, then the 

 remainder, deducting the oxygen and water 

 which have been added, must give the com- 

 position of the bile. 



Or if from the elements of the blood, we 

 subtract the elements of the bile, the remain- 

 der must give the composition of urate of 

 ammonia, or of urea and carbonic acid. 



It will surely appear remarkable that this 

 manner of viewing the subject has led to the 

 , true formula of bile, or, to speak more accu- 



