new-born, whose mucous membrane is so very permeable and lacks the protective ferments, are so very much exposed to the danger that I cannot conceive such individuals escaping infection if they be in the same room with a coughing consumptive. It has been amply proved that the air can carry not only dry but also moist tubercle bacilli. If, then, this virus be present in the air (in a measure ‘volatile’), its introduction into the mouth and so into the intestinal tract cannot be avoided. “These facts apply equally well to infants and to new-born calves.” NOTE TO PAGE 51. Mar. 3, 1904. Excellence E. von Behring, Marburg, Germany. My dear Professor Behring: I have seen in recent discussion, reported in the medical journals, a reference to Dr. Knopf in regard to the infection of record-books, which he attributed to an occurrence in the Health Bureau of Lansing, Michigan, and seems to have reported in one of the French journals. Dr. Henry B. Baker, who is the Secretary of the State Board of Health of Michigan, and who is a personal friend of mine, has been applied to for more particular information, and it appears that the matter refers to a newspaper (published in Detroit Oct. 14, 1899) and _undoubtedly refers to a claim made by some one in Russia, where such an infection is said to have taken place_. I send you herewith a copy of the notice that has been sent out by the Lansing Health Bureau, and may say that Dr. Baker writes me that nothing of the sort has occurred in the office at Michigan. I would be greatly pleased if you could send me a copy of Dr. Knopf’s publication in the _Press Medicale_ to which you have referred. Thanking you in advance, I remain Sincerely yours, KARL VON RUCK. NOTE TO PAGE 75. ... One unpleasant possibility [in the making of inoculation] is to be mentioned, one which I did not originally think of and which was called to my attention by Ober-med. Rath Lorenz. It consists in the general collapse of the inoculated calf, of very threatening aspect, when the inoculating fluid has been injected _too cold_. This happened on a Hessian farm on a cold winter day, and resulted in the collapse of _all_ the inoculated calves. (It would, by the way, have happened if only the cold fluid without the virus had been injected.) As it was, all the inoculated animals had recovered by the following day. This teaches us to warm the inoculating fluid to about body temperature before injecting it. This is readily done by placing the bottle containing the fluid into a little lukewarm water. FOOTNOTES: [1] Address delivered at the seventy-fifth meeting of Naturalists and Physicians in Cassel, September 25, 1903. [2] On the other hand, certain stages in the development of various malaria parasites resemble each other very closely; but we distinguish the parasites definitely because they are of different origin. [3] Formula for the digesting fluid: