ANIMAL CHEMISTRY. 



florid by the action of nitre, common salt, 

 k,c.; but this question has no relation to 

 the natural respiratory process. 



The frightful effects of sulphuretted hy- 

 drogen, and of prussic acid, which, when 

 inspired, put a stop to all the phenomena 

 of motion in a few seconds, are explained 

 in a natural manner by the well-known 

 action of these compounds on those of iron, 

 when alkalies are present; and free alkali 

 is never absent in the blood. 



Let us suppose that the globules Jose their 

 property of absorbing oxygen, and of after- 

 wards giving up this oxygen and carrying 

 off the resulting carbonic acid; such a hy- 

 pothetical state of disease must instantly 

 become perceptible in the temperature and 

 other vital phenomena of the body. The 

 change of matter will be arrested, while 

 yet the vital motions will not be instantly 

 stopped. 



The conductors 1 of force, the nerves, will 

 convey, as before, to the heart and intestines 

 the power necessary for their functions. 

 This power they will receive from the mus- 

 cular system, while, as no change of matter 

 takes place in the latter, the supply must 

 soon fail. As no change of matter occurs, 



no lifeless compounds are separated, neitnei 

 bile nor urine can be formed ; and the tent 

 perature of the body must sink. 



This state of matters soon puts a stop lo 

 the process of nutrition, and sooner or later 

 death must follow, but unaccompanied by- 

 febrile symptoms, which in this case is a 

 very important fact. 



This example has been selected in order 

 to show the importance and probable advan- 

 tage of an examination of the blood in analo- 

 gous diseased conditions. It cannot be, in 

 the slightest degree, doubtful that the func- 

 tion ascribed to the blood globules may be 

 considered as fully explained and cleared 

 up, if, in such morbid conditions, we shall 

 discover a change in their form, structure, 

 or chemical characters, a change which 

 must be recognizable by the use of appro- 

 priate re-agents. 



If we consider the force which determines 

 the vital phenomena as a property of cer- 

 tain substances, this view leads of itself to 

 a new and more rigorous consideration of 

 certain singular phenomena, which these 

 very substances exhibit, in circumstances in 

 which they no longer make a part of living 

 organisms. 



APPENDIX: 



CONTAINING THE ANALYTICAL EVIDENCE REFERRED TO IN THE SEC- 

 TIONS IN WHICH ARE DESCRIBED THE CHEMICAL PROCESSES OF RE- 

 SPIRATION, OF NUTRITION, AND OF THE METAMORPHOSIS OF TISSUES. 



%* The Notes correspond with the numbers in parentheses in the text. All the Analyses quoted, 

 which have the mark * attached, have been made in the chemical laboratory of the University of 

 Giessen. 



INTRODUCTION TO THE ANALYSES. 



THE method formerly employed to exhibit the differences in composition of different 

 substances, that, namely, of giving the proportions of the various elements in 100 parts, 

 has been long abandoned by chemists ; because it affords no insight into the relations 

 which exist between two or more compounds. In order to give some proofs of this state- 

 ment, we shall here state, in that form, the composition of aldehyde and acetic acid, of 

 oil of bitter almonds and benzoic acid. 



Acetic acid. Aldehyde. Benzoic acid. 



Carbon 40-00 55-024 69-25 



Hydrogen 6-67 8-983 4-86 



Oxygen 53-33 35-993 25.89 



Oil of bitter almonds. 



79-56 

 5-56 



14-88 



Now aldehyde is converted into acetic acid, and oil of bitter almonds into benzoic acid, 

 simply by the addition of oxygen, without any change in regard to the other elements. 

 This important relation cannot be traced in the mere numerical results of analysis as 

 above given ; but if the composition of the related compounds be expressed in formulae, 

 according to equivalents, the connexion in each case becomes obvious, even to him who 

 Knows no more of chemistry than that C represents an equivalent or combining portion 

 of carbon, H an equivalent of hydrogen, and O an equivalent of oxygen. 



Formula 



J^ 



Formula 



of acetic acid. 



of aldehyde. 



C 4 H 4 2 . 



of benzoic acid. 



C 14 H 6 O 4 . 



of oil of bitter almondi. 



C 14 H 6 O 2 . 



