FIELD T-Z 

 Columns 58, 59, 60, and 61 



increase In survival time. Symbol 1753. 178 



Slowing of progress of a non-fatal dis- 

 ease must be evaluated by criteria 

 other than 12 or 57. 



1752 Restraint of the infectious or non- 



infectious existing pathology. (Re- 

 striction of the disease intensity to a 

 given level or to a given range of 

 intensity indefinitely, not permitting it 

 to progress to a normal peak or to cause 

 death. ) 



1753 Delay of death due to the pathology (in 



Field E) which is fatal to untreated 1781 



controls; increase in survival time. If 



death is prevented in all individuals 1782 



which are affected with the disease 



and to which the test compound is 



administered, use another symbol to 



describe the amelioration (Symbol 1711, 



172, or 1752). Delay of death is 



ordinarily evaluated in Field Y by 



Criterion 12 or 57, coding the increase 



in survival time in Field U. 



1754 Decrease in the number of deaths due to 



the pathology (in Field E) which is le- 

 thal (or which causes a known mean 

 mortality rate) to untreated controls; in- 

 crease of the number of survivors of 

 such a pathology. If all treated organ- 

 isms are permitted to survive such a 

 pathology or if the increased number of 

 survivors is known to be also an in- 

 crease of cure or restraint, use Symbol 18 

 1711, 172, or 1752, instead of Symbol 

 1754. If Symbol 1754 is used, evalu- 

 ation in Field Y must be on the basis of 

 per cent decrease of deaths and the ex- 

 pression, decrease of the number of 

 deaths, should be used in the written 

 portion of Field T-2. 



176 Abortion of early infection. Use Symbol 



174 rather than 176 to code prevention 181 



of an infection. 



177 Decrease of the effect of a specific 



toxin of a pathogenic organism. 

 (Administration of the test compound 

 with the extract of, or killed cells of, 

 a pathogenic organism. ) The toxin, 

 which should have been given a specific 

 code identity, should be coded in 

 Field D. If the test compound antidotes 

 the toxic action 100%, use Symbol 1771. 

 1771 Prevention of the effect of a specific 1812 



toxin (coded in Field D) of a pathogenic 

 organism. (If the effect of the toxin is 

 only decreased less than 100%, use 

 Symbol 177. ) 



Protection (for skin and mucous mem- 

 branes, coded in Field H-1 or I). Pre- 

 vention of damage due to physical 

 agents such as radiation, temperature 

 extremes, etc. Use Symbol 178 also 

 for coding the chemical's prevention of 

 penetration by pathogenic organisms 

 such as trematode larvae, nematode 

 larvae, or arthropod larvae. Use 

 Symbol 1781 or 1782 only when the 

 specific nature of the protection, as 

 defined by those symbols, is known. 



Protection that is essentially mechanical 

 in character. (See Symbol 178. ) 



Protection that is essentially chemical 

 in character. (See Symbol 178. ) 



Symbols of the following series, 18--, 

 are used generally only for indicating 

 normal growth, reproduction, etc. , of 

 pathogenic or non-pathogenic micro- 

 organisms maintained on non-living 

 hosts such as nutrient agar or broth. 

 (Use symbols of the 17-- series for 

 pathogenic microorganisms on living 

 hosts. ) If, for any reason, a non- 

 pathogenic microorganism were treated 

 on a living host, this 18-- series might 

 be used. 



Growth of the microorganism colony; 

 number of individuals in a cultured 

 colony. Symbol 181 or 1812 is always 

 preferred to Symbol 18, except when 

 the author does not distinguish an 

 inhibitory chemical action as being 

 lethal (1812) or merely repressive (181), 

 in which case Symbol 18 may be used 

 (with Symbol 3 of Field T-1). 



Growth of the microorganism colony; 

 number of individuals in a cultured 

 colony. Use Symbol 181 for either 

 general decrease (stasis) or general 

 increase in the microorganism on the 

 non-living host; if the decrease is 

 demonstrated to be specifically a 

 lethal effect on all or any percentage 

 of the microorganisms in the colony, 

 use Symbol 1812. Use Symbol 1, 2, 

 or 3 in Field T-1. 



Death of the microorganism. (Use only 

 with Symbol 7 of Field T-1. ) Use 

 Symbol 1812 if a lethal ('cldal) action 

 has been demonstrated on any percent- 

 age of the microorganism individuals 

 or on any percentage of the colony. 



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