6-. University of Michigan 



It also seems to me that the argument advanced by the 

 Commission in Opinion 19 is apphcable to this case. 



If. for any reason, it should be contended that the hrst rule 

 laid down in Opinion 46 as above quoted was not intended 

 to apply to a case like this, then 1 would further urge that it is 

 a cardinal principle in the legal construction of precedents 

 that the determination of a court of final resort is a precedent 

 only for subsequent cases involving the same essential facts. 



If any of the essential facts in a subseq.uent case is dif- 

 ferent, the prior case is not a precedent that is binding on the 

 court, but may be construed or modified as the court may 

 deem necessary in dealing with the facts of the subsecjuent 

 case. 



While the language on j^age 107, Op. 46, "that the first 

 species published as a member or members of the genus are 

 the only species available as the type'" would, if taken by itself 

 and construed literally, seem to cover the case of verrucosa, 

 the language used must necessarily be construed to mean that 

 such subsequently described species agrees with the original 

 generic diagnosis. 



The fact that such subsequent species might not fall within 

 the generic specification Avas, evidently, not called to the atten- 

 tion of the International Commission. Such a possibility is not 

 mentioned in their opinion and was not passed upon. by them. 

 This being so, the essential differential fact in this case th.at 

 the subsequent species does not fall within the generic diag- 

 nosis raises an entirely new and dififerent question for which 

 the decision given is not necessarily a precedent and which is 

 still open for discussion and decision upon its merits. 



But it seems to me that the question is really covered by 

 the statement in the opinion that ''each new genus, therefore, 

 contains all the species of the Avorld, which come in that cate- 



