Januaet 2, 1920] 



SCIENCE 



15 



their occurrence in the ancient vertebrates 

 except that their course of growth is modiiied 

 by the histology of ancient bone. In the 

 absence of definite lamellaa the mycelia often 

 seek out a lacuna, enter it and growing out 

 along the direction of the brief canaliculi, 

 espand both the lacuna and canaliculi until 

 the entire structure is disrupted and the 

 canals meet other canals growing out from 

 adjoining lacunae. In modern human bone 

 the mycelia very often follow the inter- 

 lamellar spaces, but ancient bone has seldom 

 any definite spaces of this kind and more 

 often is to be regarded as an osteoid sub- 

 stance. That the appearances described for 

 the enlarged lacunae are not normal is easily 

 checked by a study of normal lacuna in the 

 adjacent material. A single microscopic field 

 will show both normal and invaded lacimae. 

 The canals, from 2-4 micra in diameter have 

 an undulating course and offer easy channels 

 of entrance to invading bacteria. 



The presence of these thread moulds would 

 seem to indicate that the piece of bone show- 

 ing them was preserved in a moist sandy or 

 muddy place close to the shore, thus agree- 

 ing with our previous conceptions of the pres- 

 ervation of fossil material. It is difficult to 

 see how the moulds would find entrance if the 

 material were embedded under sand or silt in 

 deep water. The ancient Egyptian mummies, 

 buried for thousands of years in the dry sand 

 of Nubian deserts do not show such canals, 

 nor do the Cretaceous vertebrates from Kansas 

 show them. Seitz has figured them, though 

 apparently did not recognize their nature, in 

 the bones of Labyrintliodonts and dinosaurs, 

 and I have seen evidences of them in sections 

 from the vertebra of an American sauroped 

 dinosaur. 



The bacteria doubtless have entered the 

 bone along the course of the Canals of Boux 

 and may be detected at first by the beady, 

 nodular appearance of the canal. Often the 

 bacteria, in Bothriolepis, for instance, have 

 invaded a canaliculus which the MyceUtes 

 did not find. The small clumps, or nodes, 

 may clearly be regarded as colonies of bac- 

 teria and doubtless as a form of the Micro- 

 coccus, described by Eenault in the canaliculi 



of Permian fish bone. The beady appearance 

 of an invaded canal of Roux or canaliculus 

 recalls exactly the pietiu-e of the invaded 

 dentinal tubules in cases of human dental 

 caries. We are, of course, in this case, as in 

 the case of other ancient phenomena, arguing 

 from the known to the unknown. Here is an 

 ancient situation which parallels a similar 

 modern situation and the argument is sound 

 because on it for over one hundred years we 

 have built the science of paleontology. 



These conditions can not be regarded as 

 disease in any sense, but are rather to be 

 regarded as the agents of decay in ancient 

 times. They are the agents of decay and dis- 

 ruption at the present time and from present 

 evidences the same agents of decay have been 

 at work for many millions of years, at least 

 since Devonian times. Eoy L. Moodie 



Department of Anatomy, 

 Univeksity of Illinois, 

 Chicago 



vibration rate of the tail of a 

 rattlesnake 



Through the courtesy of Professor H. E. 

 Dill, curator of the natural history museum, 

 opportunity was offered to make a brief study 

 of the rate of vibration of the tail of a dia- 

 mond back rattlesnake, Crotalus Adamanteus. 

 This specimen came from Texas on September 

 15, 1918, but had been in captivity for some 

 time previously. Its age is not known, as 

 that can not be accurately determined from 

 the number of rattles, some of which are 

 known to have been broken off, and two of the 

 nine or ten remaining are in poor condition. 

 A new rattle is formed with each moulting, a 

 process which has occurred twice during the 

 nine months that the animal has been in the 

 laboratory; the second moulting occurred six 

 months after the first. The snake is about 

 five feet four inches in length and rather 

 thin, since it refuses food. It accepts water, 

 however, and in the latter part of March two 

 sparrows were forcibly fed to it. It is exceed- 

 ingly alert and vigorous, and frequently strikes 

 at any object that is near its wire cage. It 

 has learned some discretion, and does not risk 

 the resultant bump against the wire unless 



