PROBLEMS OF PHYSIOLOGICAL CHEMISTRY. 515 



minute beings. The supposition that one variety of bacteria can pro- 

 duce lactic acid, another butyric acid, a third caproic acid, has recently 

 been stigmatized as "superstition"; but it was forgotten that the cells 

 of the hog's liver produce a different acid from that obtained from the 

 liver of a goose, ox, or man a fact which evidently is of the same 

 order as that given for the bacteria. 



Another point deserves our special attention the, inner organiza- 

 tion of the single cells, and the organisms composed of them. Since 

 our present means are insufficient to distinguish this with certainty, 

 we consider the cell or living protoplasm as being without structure. 

 This reasoning is untenable, as it is only supported by the imperfec- 

 tion of our apparatus and methods ; on the contrary, other weighty 

 facts are in favor of the presence of such an organization. Above all, 

 it is to be emphasized that within each living cell a number of chem- 

 ical processes are constantly taking place simultaneously, all of which 

 are necessary for the existence and vitality of the cell. These proc- 

 esses are of so different a nature that it is difficult to believe that they 

 take place within a perfectly homogeneous mass. It seems much more 

 simple and natural to suppose that each of the reactions takes place 

 separately, which could be most readily effected by an internal organi- 

 zation of the cell. The peculiar figures which have been noticed in 

 the division of the cells also speak in favor of this, as do the differ- 

 ences in their exterior forms, which are always governed by the inner 

 organization ; the variations in the further development, and particu- 

 larly the effect on the surroundings, are also in favor of this view. 

 How can we perceive that the bacteria of ordinary putrefaction are 

 comparatively harmless, while the bacteria of splenitis are so destruc- 

 tive, unless we seek the cause in the peculiar inner structure ? 



Hence the chemical processes within the living cell are of two 

 kinds : those in which ferments take part, and those in which they do 

 not. The ferments are definite chemical compounds, which are able 

 to decompose large quantities of other substances without undergoing 

 any apparent change themselves. The manner in which this takes 

 place is not yet explained, but we have reasons for comparing these 

 processes with others in which a small quantity of one body, e. g., 

 sulphuric acid, gradually converts a large quantity of another, e. g., 

 alcohol, into ether and water. In this case the sulphuric acid acts like 

 a ferment on the alcohol, and the similarity is so striking that it has 

 been attempted to explain both in the same way. Formerly it was 

 supposed that the simple contact of one body with another was in 

 many cases sufficient for complete decomposition, and contact action, 

 produced by the so-called catalytic force, was spoken of. Later it was 

 found that in the above example the sulphuric acid first combines with 

 the alcohol to form ethylsulphuric acid, which is afterward decomposed 

 with a fresh quantity of alcohol into ether and sulphuric acid. Ac- 

 cordingly, the action of every ferment must be considered as consist- 



