Ferments, etc., Summary 851 



Are we dealing with a living being reduced in its elementary 

 structure to a single cell or a small number of cells? Since its 

 vital activity is generally manifested to us by phenomena known 

 by the name of true fermentations (alcoholic, acetic, lactic, and 

 putrefactive), its death will result in the permanent stoppage of 

 these phenomena, unless new ferments are sowed. 



Or, to go at once to the opposite extreme, are we dealing with 

 an animal which is very complex in its structure? The anatomical 

 elements which form its tissues are threatened with death. Those 

 among them which in biochemistry played the part of formed fer- 

 ments cease to act, or lose energy of action. The phenomena of 

 zymotic fermentation which take place both without and within 

 them lose intensity and degenerate. Their personal qualities, their 

 contractility, their power of transmitting stimuli or of changing 

 them into reaction become modified and tend to disappear. 



Hence come the general lessening of the chemical phenomena 

 of life; the decrease in oxygen consumption, in carbonic acid pro- 

 duction, and in excretion of urea; the appearance in the urine of 

 sugar which is no longer sufficiently broken down; and finally, an 

 enormous lowering of the temperature. 



And at the same time, — since whenever a great and rapid dis- 

 turbance affects the equilibrium of the functions of a higher animal 

 (hemorrhage, asphyxia, etc.) , it is the central nervous system 

 which, as it is the first to be stimulated, shows by its violent reac- 

 tions the danger which threatens the whole organism, — there appear 

 these convulsions which give evidence by their persistence after a 

 return to normal pressure that a profound chemical change has 

 taken place in the tissues of the spinal cord or in the blood which 

 supplies them and would thus bring them a kind of poison. Last 

 come the muscular contractions modified in their behavior, like 

 cramps, such as occur in every dying muscle. 



Between these two extremes, the isolated cell and the warm- 

 blooded vertebrate, all the intermediaries: on the one hand, molds, 

 algae, seeds, vascular plants; on the other, annelids, mollusks, in- 

 sects, fish, reptiles. The whole aggregation of living beings, in a 

 word, dies absolutely when the oxygen tension rises high enough. 

 Not one, we can affirm, would withstand a tension corresponding 

 to the pressure of 20 atmospheres of air. We shall return to the 

 inferences suggested by this unexpected phenomenon. 



iSee my Memoire sur la -vita-lite des tissus anlmaitx (Annates des sciences natureltes. 



Zoologie, 1866). , , . , .. A , . ,' ., , 



2 Paul Bert. Note on a certain sign of approaching death in dogs subjected to rapid blood- 

 letting (Memo-ire de la Societe des sciences de Bordeaux, Vol. IV, p. 75, 1866). 



3 Contributions to the study of venoms: scorpion venom. Comptes rendus de la bocxeU de 

 biologie pour 1865, p. 136. . . . ^ , , „, ,, . 



4 See the discussions of MM. Davaine, Jaillart, and Leplat: Comptes rendus de I Acadimte 

 des sciences, Vol. LXI, 1865. 



