. 
. TRANSACTIONS OF SECTION D. 855 
or benzole, and are to a certain extent soluble in these substances when heated. 
If the threads are heated dry they readily melt. This would indicate them to be 
of the nature of resin or balsam. When examined microscopically these threads 
are seen to run longitudinally in the inner cortex occasionally, but most fre- 
quently in the phloem, between the sieve-tubes and the well-marked companion 
cells. Only in a single instance was one seen to branch. In the leaf they 
accompany the vascular bundles generally on both sides of the phloem, and 
terminate among the collecting cells on the upper side of the leaf. 
In the fruit which the author had examined the threads are much more 
numerous, and are shown to be contained in cells which have a thicker cellulose 
wall here than in the phloem, where they are very delicate indeed. He takes 
them to be of the nature of latex cells, though their contents are more homogeneous, 
never showing starch grains or other granules. It is curious to find this resinous 
substance within the cells, in spite of the statements of De Bary, Tsirch, and 
Volkens, that these substances are never found as such within the cells, but are 
passed through the cell wall as resinogenous substances, and that the resin itself 
is formed outside the cell. 
5. On an Abnormality in Tropeolum, with remarks on the origin of the 
Spur. By Professor A. Denny. 
6. Notes on the Natural History of Hierro and Graciosa, two outlying 
members of the Canary Islands. By the Rey. Canon Tristram, F.B.S. 
7. Contributions to a Knowledge of the Composition of the Human Lens, espe- 
cially in reference to the changes it undergoes with age and in cataract. 
By Wivu1aM Jos Couns, M.D., M.S., B.Sc., FRCS. 
This research was undertaken as being ancillary to the question of the pro- 
priety of extraction of immature cataracts. It was found that information on 
the subject of the varying composition of the human lens in regard to solids, water, 
 &¢., in relation to age was very meagre. The difficulty of obtaining clear, fresh, 
human lenses for analysis restricted the number of observations and extended the 
duration of the research; the value of the data obtained is enhanced by the iden- 
tity of procedure in each case. Post-mortem material was not employed. Inci- 
dentally the research corroborated some previous work on the increased weight of 
the lens with advancing age. The weight, total solids, water, and ash, and the 
percentage proportion of the three last to the first, are set forth in the case of 
twelve clear human lenses at ages 4 to 68 in the following table : 
. Total Percentum 
No. Age Weicht | Water Solids Ash 
7 Water Solids Ash 
1 4 151 103 048 003 68 32 19 
2 6 183 139 044 -002 76 24 1:0 
3 i 143 ‘096 047 ‘001 67 33 ti 
4 9 "180 "109 ‘O71 “001 61 39 “5 
5 10 163 113 050 ‘001 69 31 6 
6 | 11 *200 154 046 ‘001 106 23 5 
7 26 "215 153 062 “002 71 29 9 
8 27 188 136 “052 ‘001 72 28 5 
9 28 *1915 132 *0595 002 69 31 1:0 
10 40 "2175 "1575 ‘060 ‘001 72 28 5 
ll 64 "247 176 ‘O71 ‘001 71 29 “4 
12 68 *210 "135 “075 003 64 36 14 
Average. .} 1908 "1336 ‘0571 ‘0016 70° 30° 
. eee 
