982 REPORT—1896. 
In certain abnormal conditions either group may be affected separately or 
together. 
Under abnormal conditions leucocytes are found exhibiting both oxyphile and 
basophile granulation at one time. 
5, Some Points of Interest in Dental Histology. 
By F. Paur, £.R.C.S., Liverpool. 
The author sketched the development of teeth, and referred more in detail to 
various unsolved points. In regard to the enamel organ he explained the cavities 
or spaces frequently met with near the dentine as due to uncalcified processes of 
dentine matrix. All spaces or tubes in enamel were between and never within the 
prisms, and were due to imperfect calcification or absence of intercellular 
substance. In regard to calcification of dentine and enamel, he thought that the 
question of ‘conversion or secretion’ had caused the essential difference in the 
process as occurring in the two tissues to be overlooked. In enamel the change 
occurred in connection with the cells, whilst in dentine, as in other connective 
tissues, the change was effected by the cells on the intercellular matrix. He 
believed tubular enamel to be more common than was supposed, since in appear- 
ance it resembled dentine, though its tubular structure was due to a totally 
different reason ; indeed, tubular enamel was a negative picture of tubular dentine, 
the tubes being represented by the intercellular matter in enamel and by the cells 
in dentine. 
Another point which has been raised in regard to the enamel organ was the 
presence of blood-vessels in the enamel jelly. Professors Howes and Poulson have 
stated that this structure in the rat was vascular. The author had never yet seen 
a vessel inside the enamel organ. He believed the contrary cbservation was a 
mistake, and showed slides to explain how it might have originated. In some 
animals the stellate-celled connective tissue of the sac is almost indistinguishable 
from the stellate cells of the enamel organ, whilst the condensed tissue of the 
outer limit of the sac might easily be mistaken in small animals for the atrophying 
external enamel epithelium. This connective tissue is, of course, highly vascular, 
and if assumed to be the enamel jelly would lead to the error. 
The structure of Nasmyth’s membrane was another moot point. It was, how- 
eyer, readily shown to be an epithelial tissue if unworn fresh teeth were placed 
in a decalcifying phloroglucin solution for a few minutes, washed, stained in 
Ehrlich’s acid heematoxylin and washed again. On now peeling off and mounting 
the loose bits of membrane in Farrant’s solution they would be found to show 
epithelium with the nuclei well stained. Nasmyth’s membrane was without 
doubt a remnant of the external enamel epithelium, 
6. The Effect of the Destruction of the Semicircular Canals upon the 
Movement of the Hyes. By Epcar Stevenson, JfD., Liverpool. 
The semicircular canals were destroyed on both sides in a small dog, an 
interval of some weeks being made between the operations on each side. Com- 
parison of the eye movements before and after one ear had been operated on 
showed a very marked difference in the mobility of the eyes. The right ear was 
first treated, and it was found that the right eye lost about three-quarters of its - 
power of movement in any direction, the permanent position of the eye being a 
divergent squint, showing only very slight concomitant movements with the other 
eye. The results after the left ear had been operated on were even more 
striking, for now both eyes lost almost altogether the power of movement, the 
muscles supplied by the third nerve seeming to suffer most, a double divergent 
squint being now produced. The movements before and after operation were 
tested both by observation—the dog’s head being held fast and food being passed 
in front of him in various directions—and also graphically by means of Professor 
