“Scientifically speaking, from 300,000 to 500,000 bacteria per cubic centimeter.”
“Do we drink all those things when we have a glass of milk, Dr. Strong?” inquired “Manny” Clyde, the oldest boy.
“Four or five times that many for every teaspoonful,” said the doctor. “But it isn’t as bad as it sounds, Manny. One hundred thousand is considered a fairly safe allowance, though very good milk—the kind I drank when it was thirteen days old—may contain only two or three thousand. When the count runs up to half a million or so, it shows that some kind of impurity is getting in. The bacteria in your milk may not be disease germs at all; they may all be quite harmless varieties. But sooner or later, if dirt gets into milk, dangerous germs will get in with it. The high count is a good danger signal.”
“If Bliss, the farmer, has been allowing dirt to get into the milk, he’ll find himself out of a place,” said Mr. Clyde decisively.
“Don’t be too hard on him,” advised the doctor. “His principal fault is that he’s getting the milk dirty trying to keep it clean. He is washing his cans with water from an open well near the barnyard. The water in the well is badly contaminated from surface drainage. That would account for the high number of bacteria; that and careless milking.”
“And on that account you advise me to give up the milk?” asked Mr. Clyde.
“Only temporarily. There are other more immediate considerations. For one thing, there are both diphtheria and typhoid near by, and the people on the farm are in contact with them. That’s dangerous. You see, milk under favorable conditions is one of the best cultures for germs that is known. They flourish and multiply in it past belief. The merest touch of contamination may spread through a whole supply, like fire through flax. One more thing: one of your cows, I fear, is tuberculous.”
“We might pasteurize, I suppose,” suggested Mrs. Clyde anxiously.
Dr. Strong returned a decisive negative. “Pasteurized milk is better than poisoned milk,” he said; “but it’s a lot worse than good raw milk. Pasteurizing simply means the semi-cooking of all the varieties of germs, good and bad. In the process of cooking, some of the nutritive quality is lost. To be sure, it kills the bad germs, but it also kills the good ones.”
“Do you mean that some of the germs are actually useful?” asked Mrs. Clyde.