OCTOBEE 5, 1900.] 



SCIENCE. 



517 



small diplopod, Polyzonium rosalbum,^ but as 

 this occurred after several hours of miscel- 

 laneous collecting in which my hands had 

 been in contact with many plants, as well 

 as with other myriapods and insects, the or- 

 igin of the scent could not be indubitably 

 established. The observation was subse- 

 quently repeated both in Central New York 

 and on Long Island, but there has been 

 no opportunity to follow the matter up 

 until the present season. Learning that 

 Polyzonium is abundant in the town of 

 Farmington, Ontario County, New York, I 

 asked my friend Mr. Edgar Brown to send 

 a number of living specimens to me at 

 Washington. These have recently arrived 

 in good condition and have made a satis- 

 factory exhibition of their camphor-produc- 

 ing powers. From a full-grown specimen 

 taken between the thumb and finger no 

 odor is usually perceptible at first, but as 

 the animal struggles to escape, and especi- 

 ally if slight pressure be exerted, the char- 

 acteristic smell of camphor becomes very 

 distinctly appreciable. If a lens be used 

 at the same time, a milky fluid is seen to 

 exude from the dorsal pores, a pair of 

 which is to be found on each segment be- 

 hind the fourth. On exposure to the air 

 the liquid very quickly takes on a sticky 

 consistence and may be pulled out into 

 threads half an inch long or more. In ad- 

 dition to the smell there is also the flavor 

 and sharp burning taste of camphor, lasting 

 for a minute or two. The odor is likewise 

 not persistent, gradually decreasing and 

 finally disappearing in a short time. 



To eliminate any possibility of error re- 

 garding the odor or the material it repre- 

 sents, the animals were submitted to Dr. 

 Oscar Loew who agrees to the diagnosis 

 and informs me that no other substance is 

 recorded as having an odor likely to be 

 mistaken for that of camphor, f and that 



* Ocinglena bivirgaia Wood is probably a synonym, 

 t In this connection it may be noted that while 



the existence of camphor as an animal se- 

 cretion is still quite unknown. This does 

 not, of course, exclude the possibility that 

 a new compound is involved, but, as Dr. 

 Loew admits, a chemical analysis of this 

 animal camphor would require many thou- 

 sands of the myriapods, while the human 

 nose furnishes, after all, one of the most 

 delicate of chemical tests. For present 

 purposes, then, we must admit camphor as 

 an animal as well as a vegetable substance. 

 In the economy of the secreting animal, 

 camphor is undoubtedly to be looked upon 

 as a physiological substitute for the prussic 

 or hydrocyanic acid employed in the myria- 

 pods of the order Merochseta (Polydesmus and 

 its allies) as a means of defense. The liquid 

 is secreted in special glands opening on 

 the surface of the segments at the so-called 

 repugnatorial pores. In these flattened, 

 twenty-segmented forms, as in Polyzonium, 

 the repugnatorial secretion seems merely to 

 well up in the pores and spread itself or 

 stand in globules on the surface, whence it 

 evaporates into the air and serves its pur- 

 pose merely through the strong pungent 

 odor. But in the cylindrical or luliform 

 types of Diplopoda, and particularly in the 

 large tropical genera Spiroholus and Spiro- 

 streptus, the repugnatorial apparatus is 

 much more highly developed, so that the 

 animals are able to eject to a distance of 

 several inches a spray of a substance hav- 

 ing a very powerful, acrid odor quite differ- 

 ent from that of prussic acid. This im- 

 camphor has been known hitherto only as a vegetable 

 product it is not confined to a single plant or natural 

 order. The principal commercial supplies come from 

 Cinnamomum camphora of the family Lauracete, a 

 near relative of the cinnamon, but the Borneo cam- 

 phor is differently formed by a tree {Dryobalanox^s 

 aromatica) of the family Dipterocarpacefe, while still 

 another source is said to be Blumea balsamifera, a 

 Chinese composite herb. These substances as well as 

 the artificial camphor produced from spirit of turpen- 

 tine and hydrochloric acid, though not identical in 

 composition nor in physical properties, are closely re- 

 lated by their chemical structure. 



