506 Dr. S. S. Zilva and Major F. M. Wells. Changes in the 



dental aspect of the subject, and, as the result of his preliminary examination 

 of some of the teeth, it was decided to investigate the matter jointly in detail. 



We had the opportunity of examining a great number of teeth derived 

 from guinea-pigs in various stages of scurvy. Some of the animals 

 succumbed to scurvy on an unsupplemented scorbutic diet, others received, 

 in addition to the scorbutic diet, solutions of weak antiscorbutic potency, but 

 active enough to delay the onset and the fatal termination of the disease ; 

 others, again, received doses of various preparations which turned out to be 

 quite inactive. The teeth of normal guinea-pigs were also examined as 

 controls. 



We have convinced ourselves that the mildest degree of scurvy which 

 could just be discovered at the 'post-raortem examination produced well- 

 defined changes in the structure of the teeth, and in our numerous examina- 

 tions we have not observed a single exception to this statement. 



In our earlier observations the teeth were ground and the hard unstained 

 sections were examined. This mode of examination revealed most of the 

 features we are about to describe, but we thought it desirable, in order to 

 bring out all the details more plainly, to adopt a convenient method of 

 staining soft sections of the teeth. Such a method was suggested to us by 

 Dr. P. P. Laidlaw, of Guy's Hospital, and we take this opportunity of 

 expressing our gratitude to him for the pains he took in helping and 

 advising us. Without his help and advice this investigation would have 

 lacked many important details. 



Method of Investigation. — For the purpose of this enquiry the lower incisor 

 and molar teeth of the guinea-pig were chosen. As in all rodents, these 

 teeth grow from persistent pulp and are never shed. The teeth while still 

 in situ in the lower jaw were decalcified and sections made in an antero- 

 posterior direction, parallel to the long axis. The teeth were decalcified in a 

 solution containing 35 per cent, of formalin, 42 per cent, of formic acid, and 

 23 per cent, of distilled water. When decalcification was complete, sections 

 were made by freezing the material in gum and then staining with hsema- 

 toxyhn. Some specimens were decalcified with phloroglucinol and nitric acid, 

 which possesses the advantage of bringing about the decalcification much more 

 quickly. 



In advanced cases of scurvy the teeth were apparently sound, but useless, 

 inasmuch as they had been loosened by the gradual absorption of the cement 

 membrane of the alveolar sockets, which had left exposed that portion 

 below the neck. As a result there must have occurred that periostitic pain 

 or something analogous which follows in the case of human patients who 

 are suffering from shrunken alveoli. These teeth also presented, in addition. 



