POISONOUS SNAKES OF NROTH AMERICA. 385 



This opportuuity has enabled me to make accurate observations upon the growth, 

 falling off, and renewal of the rattle. I am in the fortunate position of having been 

 a))le to make certain observations upon healthy specimens with good appetites, 

 which decide these questions. 



In live of my snakes the long rattles fell off independently at different times, and 

 I was now able especially to observe how rapidly these redevelop. I would first, 

 however, remark that it is perfectly natural for the rattle of the Rattlesnake to fall 

 off periodically or at irregular intervals, for the organ in question consists of dead, 

 horny tissue, developed into the well-known hollow "cones," which, while partly 

 inclosing one another to form the rattle, are yet only somewhat loosely connected 

 together. Now, it may be readily understood that such a series of links, when it 

 attains a certain length, is greatly exposed to mechanical injury, and, consequently, 

 may easily break off". Without any harm to the snake itself, this chain may be also 

 cut off or torn off" by force. This is, indeed, the simple reason why the rattle never 

 becomes particularly long, and rattles with 15 to 18 joints are rare. As a rule, the 

 rattle only lasts long enough to become 8 or 9 jointed. 



As I have already stated, I was able to follow the reproduction of the rattles in 

 the case of five of the Rattlesnakes which had lost these organs. So long as their 

 rattles remained short, the snakes were naturally also unable to make a noise. But 

 the joints were gradually replaced, and in such a way that in all cases, in the course 

 of from three to four mouths, two new ones were added to the remaining (now termi- 

 nal) joint. Three-jointed rattles like these produced already a fairly loud sound. 

 In the course of a year the rattles developed into chains with from 5 to 6 joints, and 

 were then capable of producing the usual intense rattling sound. The reproduc- 

 tion of the rattles had no connection with the recurring sloughing of the skin. It 

 is well known that the epidermis is shed without the rattle, separating close to the 

 margin of the latter, and, indeed, in such a way that the end of the tail in the cast 

 skin is represented by an aperture with finely notched edges corresponding to the 

 rows of scales. 



It consequently follows from my observations that a joint of the rattle can be 

 produced in the course of every two to three months (during winter, autumn, and 

 spring, of course by means of artificial warmth, the growth of the rattle evidently 

 proceeding much more slowly in the natural state), and I do not understand why 

 other observers have not noticed the growth of the rattle in captive Rattlesnakes. 

 Probably the snakes were kept under conditions unfavorable for their welfare, 

 whereby the vital processes were checked. Perhaps, too, the observations were not 

 conducted with sufficient care. 



Dr. Feoktistow's strictures upon previous observers are not quite well 

 founded, for Dr. Holbrook has recorded, as early as 1838, that Leknew 

 two joints to have been added in one year, and that Dr. Bachman had 

 observed four produced in the same period.* It has also been stated 

 before that Dr. Cotton, of Tennessee, "had a Eattlesnake which shed 

 its skin on an average twice a year, and he observed a new link to the 

 rattle on each shedding." t 



The observations made by the Russian naturalist do not in all parti- 

 culars agree with those of a somewhat later investigator, whose facilities 

 were not inferior. On the contrary, Mr. J. J. Quelch, who conducted 

 his experiments with snakes born in confinement in the museum in 



* N. Am. Herpet., 1 ed., ii, 1838, p. 85 ; 2 ed., iii, 1842, p. 11. 

 t Hopley, Snakes, 1882, p. 298. 



H. Mis. 184, pt. 2 25 



