Studies in Paleopathology 



377 



definite geological horizon, that such and 

 such an animal existed at the time the for- 

 mation was being deposited, provided, of 

 course, the deposit is a primary one and the 

 fossil was not moved by shifting in a sec- 

 ondary deposition. 



All that we know of the earliest land 

 vertebrates, prior to the Pennsylvania!!, for 

 instance, is a single footprint from the 

 Devonian, and a few series of footprints 

 from the Mississippian. On the basis of 

 these footprints we are able to say definitely 

 that there existed in North America a di- 

 versified fauna of vertebrates, probably 

 amphibian, which preceded the well-known 

 amphibian faunas of the great Coal Period. 



DEFINITION OF DISEASE AS USED IN 

 THIS STUDY 



Disease, as the term is used in this study, 

 may be defined as any deviation from the 

 healthy or normal state of the body which 

 has left a visible impress upon the fossilized 

 skeleton. The evidence may take the form 

 of broken bones, tumors, necroses, hyper- 

 plasias and arthritides of various kinds. 

 Only the diseases of animals have been 

 considered. This is done with a full realiza- 

 tion of the enormous domain of phyto- 

 pathology and is a confession of a limitation 

 to a restricted field. Some of the paleo- 

 botanical literature has been read, but ap- 

 parently no attempt has been made to 

 trace the rise and progress of phytopathol- 

 ogy from fossil material. 



This is doubtless due to the unsatisfactory 

 condition of fossil plant material which is 

 usually quite fragmentary. Some idea of the 

 nature of plant diseases of the past may be 

 had from the following brief summary 15 for 

 which I am indebted to Professor Edward 

 W. Berry: 



"Bacterial and fungus activity are 

 known in Carboniferous plants, and would 



15 Berry: Letter to author, Jan. 4, 1918. 



16 Berry: "Remarkable Fossil Fungi," Mycologia, 



probably be detectable at much earlier 

 horizons if petrified material of greater 

 age were available for study, since the 

 bacteria appear to be among the earliest 

 forms of life. Material preserved as im- 

 pressions at all horizons, more especially 

 the post-Paleozoic ones, show abundant 

 leaf-spot fungi, and such remains from the 

 Cretaceous and Tertiary show abundant 

 insect galls and leaf cutting by cater- 

 pillars or bees; but this class of material 

 is usually more or less indefinite. When- 

 ever one handles much petrified mater- 

 ial, one is struck with traces of fungal 

 ravages and bacterial action." 



EVIDENCES OF DISEASE IN FOSSIL PLANTS 



It is often difficult to decide whether the 

 ravages of fungi and bacteria are pre- or 

 post-mortem. The agents of decay are well 

 known to have existed early in geological 

 time. During the Carboniferous there ex- 

 isted conditions which were especially favor- 

 able to the growth of a mycological flora, 

 and much of it was probably on dead 

 plant material. 



Professor Berry writes further 16 con- 

 cerning the primitive fungi: 



"Among the relics of former vegetation 

 that carry the record back many millions 

 of years the remains of fungi are so rarely 

 found that their presence is always ex- 

 ceptional, although it is obvious that 

 many times during the long history of the 

 earth the environment has offered opti- 

 mum conditions for their abundant de- 

 velopment. To mention but one such 

 occasion, that of the formation of the 

 Coal Measures must have witnessed an 

 exceedingly abundant mycological flora. 

 That these plants were present thus early 

 is indicated by the abundance of hypha?, 

 and other traces of fungal activity such 

 as butyric fermentation, in the tissues of 



19 1 6, vol. 8, No. 2, pp. 73-78, plates 180-182, con- 

 taining 16 figures. 



