Engels Classification

Each of these groups of substances may be sub-divided into four series The first three of these comprise the aliphatic compounds derived from methane (series I), ethane (series II) and propane (series III). The fourth series comprises the aromatic compounds derived from benzene and its homologues. 

All the war gases have not been included in Table XII, but only the most important. Those not included may be easily classified into their proper groups. Acrolein, for instance, in the aldehyde group, lewisite and diphenyl cyanoarsine in that of the arsines, methyl cyanoformate and ttiethyl chloroformate in that of the esters. 

According to Engel this classification allows for the allocation of gases which have never yet been employed in warfare. Stibine and phosphine, for example, may be considered as arsines in which the arsenic atom has been substituted by that of antimony or phosphorus similarly dichloroethyl selenide and telluride may be considered as ethers in which the oxygen atom has been replaced by that of selenium or tellurium. 

This and other classifications of war gases will not be considered further. 

It is possible to arrange the war gases in the chronological order in which they were first used in the war of 1914-18. This is the order employed in Table XIV at the end of this book, where the physical, chemical and physiopathological properties of the principal war gases are summarised. In the text, however, it is considered more convenient to catalogue them according to chemical relationships and similarity of structure. 

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Figure 8.3 Taxonomic classification of all living organisms. (Modified from Engel and Macko, 1993.)...

Later, other chemical classifications were proposed, and two of these will be outlined here—that of Jankovsky and that of Engel. 

Molz, R. F, Engel, P. M., Moraes, F. G., Torres, L., and Robert, M. "A Fast Prototyping Neural Network Model for Image Classification." In Proceedings of the XV Conference on Design of Circuit and Integrated Systems (DCIS), 1 (2000) 836-41. 

Engel, JJ (2006) Report of the ILAE classification core group. Epilepsia, 47 1558-1568. 

Campa JF, Engel WK. (1970) Histochemical classification of anterior horn neurons. Neurology 20, 386. 

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