It must be confessed that this rule is somewhat vague and that it would be often of doubtful application, and that on the other hand (3) is clear and easy to follow. But there are objections to (3). It would put a great many subjects under words where nobody unacquainted with the rule would expect to find them.
| Works on the | would hardly be looked for under |
|---|---|
| Alimentary canal | Canal. |
| Dangerous classes | Classes. |
| Digestive organs | Organs. |
| Dispensing power | Power. |
| Domestic economy | Economy. |
| Ecclesiastical polity | Polity. |
| Final causes | Causes. |
| Gastric juice | Juice. |
| Laboring classes | Classes. |
| Military art | Art. |
| Parliamentary practice | Practice. |
| Political economy | Economy. |
| Solar system | System. |
| Suspended animation | Animation. |
| Zodiacal light | Light. |
Another objection is that in most cases the noun expresses a class, the adjective limits the noun, and makes the name that of a subclass (as International law, Remittent disease, Secret societies, Sumptuary laws, Typhoid fever, Venemous insects, Whig party, Woolen manufactures), and to adopt the noun (the class) as the heading is to violate the fundamental principle of the dictionary catalogue. The rule is urged, however, not on the ground of propriety or congruity with the rest of the system but simply as convenient, as a purely arbitrary rule which once understood will be a certain guide for the reader. “If he is told that he shall always find a subject arranged under its substantive form and never under an adjective he can hardly fail to find it. If, on the other hand, he is told that Comparative anatomy is under C and Morbid anatomy under A, that Physical geography is under P and Mathematical geography under G, he will only be bewildered, and accuse the cataloguer of making distinctions that it requires too much study to appreciate. Theoretically the distinctions may be justified, but practically the simpler way of using the noun only is more {53} easily grasped by the common mind. And the system of classifying names under the surname is precisely analogous; [42] thus
Smith, John,
Smith, Joseph,
Smith, William,
seems to me to be arranged on the same principle as
History, Ancient,
History, Ecclesiastical,
History, Modern,