Toxins, I understand, have something to do with germs.  Their study involves, at any rate at present, a large stock of small animals, such as mice and frogs and snakes and guinea-pigs and rabbits, who are given various diseases and then studied with loving attention.  I saw the doctor’s menagerie when I went to see him about Frank; they were chiefly housed in a large room over the kitchen, communicating with the doctor’s own room by a little old powder-closet with two doors, and the smell was indescribable.  Ranks of cages and boxes rose almost to the ceiling, and in the middle of the room was a large business-like looking wooden kitchen-table with various appliances on it.  I saw the doctor’s room also—­terribly shabby, but undoubtedly a place of activity.  There were piles of books and unbound magazines standing about in corners, with more on the table, as well as a heap of note-books.  An array of glass tubes and vary-colored bottles stood below the window, with a microscope, and small wooden boxes on one side.  And there was, besides, something which I think he called an “incubator”—­a metal affair, standing on four slender legs; a number of glass tubes emerged from this, each carefully stoppered with cotton wool, and a thermometer thrust itself up in one corner.

A really high degree of proficiency in any particular subject invariably leads to atrophy in other directions.  A man who eats and breathes and dreams Toxins, for instance, who lives so much in Toxins that he corresponds almost daily with learned and unintelligible Germans; who knows so much about Toxins that when he enters, with shabby trousers and a small hand-bag, into the room of a polished specialist in Harley Street, he sees as in a dream the specialist rise and bow before him—­who, when he can be persuaded to contribute a short and highly technical article to a medical magazine, receives a check for twenty-five guineas by return of post—­a man of this kind is peculiarly open to the danger of thinking that anything which cannot be expressed in terms of Toxin is negligible nonsense.  It is the characteristic danger of every specialist in every branch of knowledge; even theologians are not wholly immune.

It was so in the case of Dr. Whitty (I forget all the initials that should follow his name).  He had never been married, he never took any exercise; occasionally, when a frog’s temperature approached a crisis, he slept in his clothes, and forgot to change them in the morning.  And he was the despair of the zealous vicar.  He was perfectly convinced that, since the force that underlay the production of Toxins could accomplish so much, it could surely accomplish everything.  He could reduce his roses, his own complexion, the grass on his garden-paths, the condition of his snakes’, and frogs’ skins, and the texture of his kitchen-table—­if you gave him time—­to terms of Toxin; therefore, argued Dr. Whitty, you could, if you had more time, reduce everything else to the same terms.  There