In studying the statistics of bovine tuberculosis of this province, I have had the hearty support of the government officials as well as of many county veterinary surgeons. After my colleague, Dr. Römer, had examined several thousand head of cattle we ceased our labors because we were confronted by the depressing fact that larger herds of cattle were rarely ever free from tuberculosis. As a test to discover the presence of tuberculosis we made use of small infections of Koch’s tuberculin. We are aware that there are tuberculous animals which do not react to this test. _On the other hand, if the method of making the test be faultless, a positive reaction always indicates that the animal in question is infected with tuberculosis._ Our figures for these cases are therefore without doubt too low. Despite this, and despite the fact that young cattle, even though infected with tuberculosis, often do not react to the usual dose of tuberculin, we found frightfully high figures for herds of more than twenty animals. We had to admit that in this respect we were no better off than other countries. I will cite one of the most experienced of the investigators of tuberculosis, Prof. Bang of Copenhagen, who says that in Denmark, in stables of more than fifty head of cattle, an average of 60% of the animals are tuberculous. Bang says further: “If one is dealing with a large herd in which tuberculosis has existed for many years, one may as well omit testing the full-grown animals. _Most of them will react, even though they appear perfectly healthy._” To this, as a result of many years’ observation, I should like to add, _and though they may apparently remain perfectly healthy for their entire life_. As a rule a herd of cattle on a large farm, though infected with tuberculosis, presents a fine appearance. Nor does their state of nutrition, milk production, or calf-raising leave anything to be desired. Now and then a cow coughs, or, despite plentiful food, loses flesh. This animal is put aside and the herd, as such, resumes its magnificent appearance. If in a herd reacting to tuberculin things are allowed to go on in this way for a number of years, especially if the cattle be barn-fed, then, to be sure, the number of coughing animals increases, the offspring deteriorate, the milk and meat production decrease, until finally the scourge of tuberculosis is plainly marked.