7 i8 



PRINCIPLES Or GENERAL PHYSIOLOGY 



The majority of the offspring were found to be spotted. For instance, when the 

 ovary and the male were pure white, the foster-mother pure black, the chickens 

 had black spots. 



Should this turn out to be correct, we see a possibility of the disputed " Sran#mi#*ton 

 ofacqiiirtd characters" since the body of the mother affects the germ plasm. In respect to the 

 question in general, the remarks of Shattock (1911, pp. 26-34) will be found of much interest. 

 He shows that the callosities of the monkey are not to be attributed to transmission of 



FKJ. 256. SECRETION OF MILK IN THE OAT, PRODUCED BY INJECTION OF PITUITARY EXTRACT 



FROM THE FOWL. 



Upper curve, blood pressure. 



Top signal, drops of milk secreted. 



Middle signal, injection of saline extract of ten pituitary glands of the fowl. 



Bottom signal, time in ten-second intervals. 



(Mackenzie, 1911, Fig. 4.) 



a character acquired by friction. A callosity acquired in this way is not transmitted, but 

 has to be regained after birth. 



The Mammary Gland. The growth of this organ is closely connected with 

 that of the uterus in pregnancy, so that it is not surprising to find that the 

 growth is affected by a hormone produced in the corpus luteum. This has been 

 shown by O'Donoghue (1911, 1 and 2, and 1913) and by Ancel and Bouin 

 (1911). The artificial production of corpora lutea by puncture of the G mafia n 

 follicles is followed by growth of the mammary gland, as shown in Fig. 255. 



The second stage, associated with secretory activity in the later period 

 of pregnancy, is independent; of the corpus luteum. It has been shown by 



