CHEMICAL BASIS OF THE ANIMAL BODY. 207 



admit of no suitably brief description. The principle involved in each 

 consists in preparing a concentrated alcoholic, ethereal or chloroformic 

 extract of the mother-substance, and from this crystalline compounds 

 of the alkaloids are prepared by the addition of suitable reagents 1 . 

 A further means for their final separation consists in the formation of 

 benzoylated compounds which are insoluble in water 2 . 



Alkaloidal substances, some poisonous, others inert, may also be 

 obtained both from normal but more particularly from pathological 

 urines 3 . 



The first distinct evidence that the poisonous properties of certain 

 (septic) fluids might be due to a specific chemical substance rather than 

 necessarily to the action of organisms in those fluids is apparently due 

 to Panum, who seems to have dealt with a septic alkaloid in a very 

 pure form although he did not definitely characterise it as a chemical 

 substance 4 . This was followed by a series of observations all tending 

 in the same direction, but none of the observers obtained the supposed 

 specifically toxic substances in forms which enabled them to be spoken 

 of as chemical individuals until Nencki in 1876 5 isolated from the 

 products of the pancreatic putrefaction of gelatin a well-crystallised 

 base C 8 H U N, to which he assigned the constitutional formula 



C 6 H 5 CH and hence the name isophenyl-ethylamin. Since 



then the ptomaines have been in most cases fairly definitely and in 

 some cases absolutely characterised as regards their chemical compo- 

 sition and constitution. They belong typically to the class of 

 substances known as amines and are in many cases diamines. Two 

 of the most clearly defined ptomaines are cadaverin and putrescin. 

 These are found in corpses which have undergone putrefactive de- 

 composition, cadaverin appearing in the earlier stages of putrefaction 

 and putrescin preponderating in the later. The latter is largely 

 present in putrid herrings 6 . The former is identical with penta- 

 methylen-diamine N"H 2 (CH 2 ) 5 NH 2 . 7 The latter has been shown to 



1 For description of these methods see Halliburton, Chem. Physiol. and PathoL 

 1891, p. 175. Otto, loc. cit. S. 103. 



2 Udranszky u. Baumann, Zt. f.physiol Chem. Bd. xm. (1889), S. 562. 



3 For details and literature see Neubauer u. Vogel, Anal. d. Harns. 1890, S. 241 

 et seq. 



4 Published originally in Danish in Bibliothek. /. Lager, April 1856, S. 253. 

 Fully abstracted in Schmidt's Jahrbucher d. ges. Med. Bd. ci. (1859), S. 213, and 

 republished in Virchow's Arch. Bd. LX. (1874), S. 301 with literature up to date. 



5 Ueb. d. Zersetz. d. Gelatine u. s. iv. Bern, 1876. See later Jn. f. prakt. Chem. 

 Bd. xxvi. (1882), S. 47. 



6 Bocklisch, Ber. d. d. chem. Gesell. Bd. xvm. (1885), Sn. 86, 1922 ; xx. (1887), 

 S. 1441. 



7 Ladenburg, Ibid. Bd. xix. (1886), S. 2585. 



