October 13, 1922] 



SCIENCE 



417 



logical laboratory at Fairport, Iowa, has re- 

 signed to become assistant professor of zoology 

 at the University of Southern California. 



Professor T. J. Talbeet, superintendent of 

 farmer's institutes and extension schools and 

 leader of subject matter specialists, Division 

 of Extension, Kansas Stat€ Agricultural Col- 

 lege, has been appointed professor of horticul- 

 ture and chairman of the department of horti- 

 culture at the University of Missouri. 



DISCUSSION AND CORRESPOND- 

 ENCE 

 THE PALEOPATHOLOGY OF THE 

 PARASUCHIANS 



Students of vertebrate paleontology have 

 long been aware of the presence of curious 

 knoib-like eminences on the snouts of the Tri- 

 assie crocodile-like, elongate reptiles which 

 Huxley regarded as the Parasuehia, but are 

 now known as the Phytosauria with an organi- 

 zation quite remote from that of the Croco- 

 dilia. No adequate explanation of these emi- 

 nences has ever been given although the writer 

 referred to one of them as a callus following 

 a fracture; an interpretation from which he 

 was dissuaded by Huene. Recently Dr. Case 

 has written me about a very curious example 

 of these eminences and Professor 0. Abel of 

 Vienna has discussed^ in a very interesting 

 manner the nature of all the eminences, regard- 

 ing them as lesions following injuries received 

 in combat, and as occurring more frequently 

 in the male. The ensuing complexities of a 

 taxonomic natui-e are startling, and if correct 

 pathological distui'bances will reduce a lot of 

 scientific names to the limbo of useless terms. 



But I am not at all sure that Abel is cor- 

 rect. His argument is from analogy only. He 

 has given not one positive anatomical or patho- 

 logical evidence to prove that the eminences 

 are "Bissverletzungen," or lesions . of a trau- 

 matic nature with often huge necrotic sinuses, 

 if they are at all pathological. The weakness 

 of Abel's argument consists in the fact that 



10. Abel: Bie Sdmauzenverletzungen der 

 Parasuehier und ihre biologische Bedeutung (mit 

 10 Textfiguren). Paleontologische Zeitschrift, 

 Bd. V, Heft 1, Juni 1922, pp. 26-57. 



the eminences are always in the median line 

 and are always fairly symmetrical, at least in 

 all the examples known to me. So before 

 Abel's conclusions are accepted and the taxon- 

 omy of the Phytosauria revised we must have 

 definite proof that these eminences really are 

 pathological in nature and not something else. 

 They may be pathological lesions, but we do 

 Hot know they are, and there are methods of 

 determining this point within reasonable 

 limits of certainty, and that is by a histo- 

 logical comparison of the bone from one of 

 the eminences, with normal bone elsewhere on 

 the snout. 



We have suificient knowledge of the histology 

 of fossil bone through the studies of Kolliker, 

 Seitz and Schaffer, whose work is reviewed in 

 my forthcoming volume on "Paleopathology," 

 and to which I have made a number of ad- 

 ditions. From the standpoint of histology the 

 bone tissue of ancient forms, and of modern 

 fishes, consists largely of an osteoid tissue 

 which in normal fossil bone has few, widely- 

 scattered lacunae, scant lamellse and little or 

 no evidences of an Haversian arrangement. 

 In fossil pathologic bone, however, the laeunse 

 become more numerous, the lamellee more 

 prominent, and numerous concentric arrange- 

 ments, recalling Haversian systems, are ap- 

 parent. I have found this to be true in cal- 

 losites of the Permian reptiles, in the Co- 

 manchie dinosaurs, in the Pleistocene eats, in 

 pre-Columbian man and in the modern bison, 

 so we may say the phenomena are universal. 

 Foote has recorded a similar fact for the 

 modern bull-frog, in a case of a fracture of 

 the femur. 



Until positive evidence of this kind is forth- 

 coming Abel's conclusions must await accept- 

 ance. The matter is far too important for 

 hasty judgment. The numerous fossil patho- 

 logical lesions I have studied are so different 

 from the symmetrical, median eminences seen 

 in the Phytosaui-da that I hesitate to accept 

 them as callosities. We usually find a lack 

 of symmetry in pathological lesions, especially 

 in those of a traumatic character. 



Rot L. Hoodie 



College op Medicine, 

 Univeesity of Illinois 



