It is hardly correct to say that because sclerosis of the carotid accompanies cataract that, therefore, the lenticular opacity is secondary to the sclerosed carotid. I submit that cataract is itself a sclerosis of the lens, and that the hardened condition of lens and carotid is merely common to both, though the carotid may possibly degenerate first. I quite agree with Dr. Angell that it is not probable that every case of cataract will show a sclerosis of the carotid, and that there may be senile marasmus, or a feebleness of the circulation after exhaustive disease, or congenital insufficiency of the arterial circulation, or abnormal growths pressing on the carotids-all and any of them as causes of cataract.
Some of the most frequent causes of cataract are, in my opinion, gout, rheumatism, rheumatic gout and syphilis, and here what benefits the gout or rheumatism will tend to better the cataract.
But my limits will not admit of my dealing with all the causes of cataract, and I therefore propose to confine myself more particularly to three that have hitherto been brought before the profession, and to which I attach very great importance. I refer to
and (c) Hard Water.
I have watched cataract cases with great care for some years, and I am prepared to maintain that the most frequent causes of cataract are the use of much salt, or of much sugar, or of hard water; very frequently we find all the three causes operating at the same time in the same individual.
Before proceeding allow me to say that I do not propose to exclude any of the other causes of cataract -no, I merely confine myself to these three as emanating from my own experience, and because I wish to call your very special attention to them. Then first as to.
Salt-Eating as a Cause of Cataract.
I lately published a little treatise entitled, Super salinity of the Blood, an Acceleration of Senility and a Cause of Cataract, and in it I claim to have proved that an excess of salt acts as a positive cause of cataract.
The proof that salt will cause cataract in the lower animals has long been given, and it has been my object, in the little work just cited, to show that not a few of the cases of cataract that we meet with are more or less due to the fact that the patients had been in the habit of partaking of too much salt with their food, or in their food, or perhaps even as a saline mineral water.
It will not be needful that, I go over much of the ground again here, as I shall not have time, but I may just give the conclusions to which I have arrived, and a few points that lead up to them.
According to the experiments of Kunde, we find that certain of the lower animals to which salt has been administered, at once get cataract. Kunde’s experiments were confirmed by other observers. Subsequently Kunde says: “(Ueber Wasser entziehung und Bildung voruebergehender Kartarakte, 1857), if you take a frog weighing 30 grammes, and give it a 0.2-0.4 dose of salt, either under the skin or in the rectum, you will, in a short time, observe a bulging out of the cornea, with an increase of the aqueous humor, and sooner or later, an opacity of the lens, which will begin, sometimes anteriorly and at other times posteriorly. This opacity increases in proportion as the animal gets weaker, and attains to such a degree at last, that the lens takes on a light ash-gray appearance.”
And again: “Two grammes of rock-salt was introduced into the stomach of a young cat, and it killed her in three hours, but the lens had turned opaque before death.”
Kunde repeated the experiment many times, but always with the same result, the lens became opaque.