84 D. NOEL PATON, B. P. WATSON, AND J. KERR ON 



combined fluids gave only a faint although a distinct reaction. For the sodium iodide 



the figures show : — 



Foetal urine .......... 04 per mille. 



Allantoic fluid -0057 „ 



Amniotic fluid ......... *0066 „ 



There was nearly ten times as much in the foetal urine as in the fluids. Such 

 observations seem to indicate that secretion from the kidneys alone would explain the 

 appearance of these substances in the fluids. 



(3) Chemical Examination of Fluids. — The marked differences in the chemical 

 constitution of urine and of exudations from blood-vessels justified us in hoping that 

 a study of the chemistry of the fluids would throw important light upon their nature. 

 Although a good many isolated observations on the chemistry of these fluids have been 

 recorded, few systematic studies of the subject have been made. The best of these is by 

 Doderlein {Arch. f. Gyn., xxxvii., Heft i. p. 141, 1890), who carried out an extended 

 series of observations on the amount, physical characters, and chemical constitution of the 

 fluids in the cow throughout pregnancy. Curiously enough, he failed to observe some 

 important points, and, in our opinion, failed also to appreciate the significance of his 

 own evidnce. 



Kestiakowski, in La Physiologiste Russe, 1898-99, p. 155, gives a series of analyses 

 of the amniotic fluid of the cow at different stages of pregnancy, and he concludes that 

 in the early part of pregnancy it is derived from the vessels of the placenta, and that 

 in the later months it is an excretion from the organs of digestion. His analyses did 

 not include the investigation of the non-protein nitrogen, and he thus failed to under- 

 stand the significance of the presence of the urinary constituents in the fluids. 



For our investigations we have chiefly used the sheep, because (l) it is easy to get 

 a considerable number of pregnant uteruses from the slaughter-house ; (2) in the sheep 

 the allantoic and amniotic sacs are both well developed. 



More recently these observations have been extended by the examination of the 

 fluids of the cow, pig, and dog. 



The results may be considered under the following heads : — 



(a) Amount, character, and specific gravity of each fluid at different stages of 

 pregnancy. 



(b) The occurrence or non -occurrence of proteins in the fluids of various animals. 



(c) The amount, character, and distribution of the non-protein nitrogen. 



(d) The pigments. 



(c) The occurrence of sugar ; its nature and amount, and its relationship to the 

 non-protein nitrogen. 



(/) The ash of the fluids. 



(a) Amount and Specific Gravity of the Fluids. — The following tables give the 

 results of our observations during 1905-6 on the sheep. Table A gives the individual 

 observation. Table B gives the average result at different stages of pregnancy. 



