344 LUTHER BURBANK 



required, it is furnished by an interesting and 

 remarkable experiment made by Professor 

 Jacques Loeb, formerly of California Uni- 

 versity, now of the Rockefeller Institute in New 

 York. Professor Loeb placed a female butter- 

 fly in a cigar box. Closing the box he suspended 

 it in mid-air between the ceiling and floor of a 

 room, and opened the window. 



"At first," says Professor Loeb, "no butterfly 

 of this species was visible far or near. In less 

 than an hour a male butterfly of the same species 

 appeared on the street. When it reached the 

 high window its flight was retarded and it came 

 gradually toward the window. It flew into the 

 room and went up to the cigar box upon which 

 it perched. During the afternoon two other males 

 of the same species came to the box." 



A commentator observed that the experiment 

 makes it unequivocally clear that insects possess 

 an olfactory sense of almost inconceivable deli- 

 cacy. But the question as to what is the real 

 character of the stimulus that produces the sense 

 of smell is one of the mysteries of science. 



"A substance like musk," he says, "may give 

 out a characteristic odor continuously for an in- 

 definite period, while the substance itself appears 

 to lose no weight. If particles of the odoriferous 

 substance are really thrown off, these particles 



