94 BIOLOGICAL DIAGNOSIS OF PREGNANCY' 



organism of the mother. The blood probably receives 

 substances perhaps also secretions which are out of 

 harmony with the plasma, and remain so ; and the time 

 is too short for the blood to accustom itself entirely to 

 these new kinds of substances. The placenta, accord- 

 ing to this point of view, together with the foetus, 

 never settles clown completely within the organism of 

 the mother. With the expulsion of the placenta, in 

 which process, again, ferments probably play a pre- 

 paratory part, the ferments which are directed against 

 its albumen disappear fairly quickly. It is, of course, 

 quite possible that these placentally active ferments 

 are conditioned by many different forces. 



The view we have just discussed gives us an oppor- 

 tunity of demonstrating the initiation of the function 



J O 



of a particular organ. Were an organ to suddenly 

 take up a particular function at a particular moment 

 -say the delivery of a particular secretion then it 

 is quite conceivable that its activities would, at first, 

 be disharmonious with the plasma. We might pos- 

 sibly expect something of this kind from the sexual 

 glands at the onset of puberty ; but experiments 

 carried on in this direction upon animals in heat have 

 not as yet given any certain result. On the other 

 hand, the cessation of the functions of a particular 

 organ might lead to the appearance of substances out 

 of harmony with the blood; for these functions clo not 

 cease suddenly, and it may be that their gradual dis- 



