higher efficiency of growth at first. In a chicken, as in a guinea-pig, birth is a disturbing factor, and growth immediately after the hatching of the chicken is a little impeded, but the chick quickly recovers and, as we see, the first time when the rate can be distinctly measured we get a nine-per-cent. addition to the weight in a single day. In a chicken as in the guinea-pig, the rate gradually diminishes. The change from the rapid decline at first to the later slower decline is more gradual; the curve is more distinctly marked in the chicken as a round curve. There is not in the bird so marked a separation of the preliminary rapid decline and the later slower decline as we find in the guinea-pig. The curve again is very irregular because I had only a very limited number of observations upon the weight of chicks. The other sex, as the next slide will show, presents similar phenomena, though the female chickens do not grow quite as fast as their brothers. Here we notice an increase
