116 



IOWA ACADEMY OF SCIENCES. 



While pursuing investigations on the teeth of the mammalia as a prepar- 

 ation for lectures on Comparative Odontography before the Dental Depart- 

 ment of the State University of Iowa, the writer became convinced that 

 there were certain radical misconceptions among anatomists and histolo- 

 gists as to the manner in which the blood is distributed to the teeth. It is 

 quite possible that this has already been correctly stated by some writer 

 unknown to me. If such is the case it is evident that little heed has been 

 given to the matter by English and American authorities, among whom I 

 have been unable to find a single clear and lucid, as well as correct account 

 of the vascular supply of the teeth. This, then, is my excuse for adding to 

 the already multitudinous contributions to the anatomy of the domestic cat. 

 Dissections and microscopic preparations of injected decalcified teeth of the 

 cat, and also of the rat, in which the entire jaw with all the teeth has been 

 ground down to the requisite thinness, show conclusively that the manner 

 in which the teeth obtain their vascular supply is not understood or at least 

 not properly expressed by the best authorities accessible to the student. 



This matter obtains a further importance in view of the sti'ong prob- 

 ability that there is no great difference between the human and feline 

 anatomy in this particular, and a likelihood that the errors in the one case 

 have been paralleled in the other. 



First— ^Yha.t is the present teaching as to the method by which the teeth 

 are supplied with blood? The following quotations will be sufficient to 

 answer this question. 



1 " The pulp contains the nerves and blood vessels of the tooth, which pass 

 into the pulp through the foramen at the point of the faug." -"This (the 

 pulp cavity) communicates with the external surface of the toolh by a small 

 aperture at the apex of the root." 3"The blood vessels and nerves penetrate 

 by a little orifice at the extremity of each root." •» "The vessels of the pulp are 

 very numerous; three or four arteries enter at the apical foramen." *"The 

 lower teeth derive their vascular supply from the branches given off to each 

 tooth by the inferior dental artery, itself a branch of the internal max- 

 illary." «"The pulp consists of a soft connective tissue, and some nerve 

 fibres which pass into the pulp cavity along with the blood vessels by a 

 minute canal at the apex of the fang." ' "The arteries and nerves, which 

 are derived from the internal maxillary and fifth pair respectively enter by 

 the aperture at the point of each faug." « "The dental and incisor arteries 

 during their passage through to the substance of the bone give off a few 

 twigs which are lost in the cancellous tissue, and a series of branches which 

 correspond in number to the roots of the teeth; these enter the minute aper- 

 tures at the extremities of the fangs and supply the pulp of the teeth." 



Dr. G V Black, in his work on the periosteum and peridental membrane, 

 eomes nearer a correct statement of the manner in which blood is supplied 

 to the teeth than any other writer whom I have been able to consult. He 

 says: 



iProf. Wm. Turner, Enc Brittanica, Vol. VII., p. 234. 



sProf. W. H. Flower, Enc. Brittanica, Vol.. XV., p. 349. 



3Human Physiology, Flint, p. 191. 



iDental Anatomy, Tomes, p., 106. 



SDental Anatomy, Tomes, p 36. 



6The Essentials of Histology, Scbafer, p. 128. 



7Quain's Anatomy, Ninth Edition, p. 550. 



SGray's Anatomy, p. 523. 



