On Certain Parasites of the Ifouth in Cases of Pyorrhcea. 525 



The cause of the deposit of hard tartar was described by 

 AV. D. Miller (11) as a chemical reaction. The CO2 in the saliva 

 was said to escape on reaching the mouth, and, the alkalinity of 

 the saliva thereby becoming greater, the salts, being then less 

 soluble, were deposited. As proof of this, test-tube experiments 

 were adduced, and the fact that more tartar is deposited on those 

 teeth near the openings of the salivary ducts into the mouth was 

 supposed to settle the matter. Exactly the same explanation is 

 given in "The Science and Practice of Dental Surgery," by 

 Bennett, in 1914. In this work it is admitted, however, that the 

 deposit of hard tartar in some positions, notably on the roots of 

 teeth which had apparently no lesion leading to the mouth-cavity, 

 presented difficulties. We have already described the positions in 

 which hard tartar is found, but we have never found any • unless 

 the Leptothrix was there depositing it. The abnormal amount 

 of tartar formed in pyorrhoea is a marked feature of the disease, 

 both in man, cat, dog, and also, we hear from Dr. Broom, in the 

 acute pyorrhcea of the golden moles of South Africa,, Chrysochloris 

 hottentota and asiatica, where not only the whole of the milk- 

 dentition is rapidly lost from this disease, but the germs of the 

 permanent teeth are so injured that tliey fail to errupt. In the 

 tonsil-crypts we have found the Leptothrix growing in large 

 colonies, some of them depositing hard tartar in their centres. It 

 is probable that tonsil-stones are due to this cause. It will possibly 

 be found on further investigation that some calcareous stones from 

 other parts of the body have the same origin. Those occurring in 

 the salivary ducts are particularly likely to be of this nature. 



It is worthy of note that the sore surface in pyorrhoea is always 

 found opposite the tartar ridge, and consequently in juxtaposition 

 to the colonies of Leptothrix with which the ridge is covered. 

 The Leptothrix follows down the recession and abounds in the 

 pockets formed. According to R. von Jaksch (7) it grows 

 abundantly in the lungs, in foetid bronchitis and gangrenous lung 

 affections. Von Jaksch says that by Leptothrix he means the 

 Bacillus maximus huccalis of Miller. If we have correctly 

 identified the fusiform body, it appears to have some relation to 

 Vincent's angina and hospital gangrene. We merely indicate 

 these positions in which the Leptothrix is found in order that it 

 may, we hope, not be entirely overlooked in future as a possible 

 cause of other diseases as well as of pyorrhoea. 



The Leptothrix was described by many early investigators 

 with varying degrees of accuracy. The first to study it with 

 detailed attention was Vicentini (IS). His descriptions of what 

 he called Leptothrix racemosa (including under this name both 

 species of Leptothrix described by Miller as well as other 

 organisms) were not altogether correct, and its pleomorphism 

 unfortunately led him to the remarkable conclusion that all forms 



