. The endocrine organs; an introduction to the study of internal secretion . tuitary autacoidis not antagonised byatropine. This may betaken as a sign thatit does not act throughnerves or nerve-endings,but directly upon thekidney cells ; in this re-spect also it resemblesthe action of secretineupon the pancreas. Effect on Secretion ofCerebro-spinal Fluid.—It has been shown byWeed and Gushing thatextracts of posterior lobealso contain an autacoidwhich stimulates theflow of cerebro - spinalfluid (fig. 63). This isnot dependent on in-crease of blood-pressure,for it may be accom-panied by a fall i
. The endocrine organs; an introduction to the study of internal secretion . tuitary autacoidis not antagonised byatropine. This may betaken as a sign thatit does not act throughnerves or nerve-endings,but directly upon thekidney cells ; in this re-spect also it resemblesthe action of secretineupon the pancreas. Effect on Secretion ofCerebro-spinal Fluid.—It has been shown byWeed and Gushing thatextracts of posterior lobealso contain an autacoidwhich stimulates theflow of cerebro - spinalfluid (fig. 63). This isnot dependent on in-crease of blood-pressure,for it may be accom-panied by a fall insteadof a rise of pressure, andby an increase in depth ofthe respirations: the in-creased flow of cerebro-spinal fluid seems tobe independent of thesecircumstances. Effect on Milk Secre-tion.—It was found by Ott and Scott that in the goat an injection ofpituitary extract into a vein greatly increases the quantity of milk whichcan be drawn from the udder in a given time after the injection, as com-pared with that which could be obtained in a similar period immediately. § g ,*5 •e o 53 ca -S ao I c«O a d o Effects of Extracts of Posterior Lobe of Pituitary 91 ~ 2 O 3 2 before. This galactagogue action of pituitary extract was confirmed inlactating cats by Mackenzie and myself. The method we employed con-sisted in canalising or in- o cising the nipple of oneor two of the mammas soas to allow any milk whichwas secreted to run milk was conductedto the side and registeredby allowing it to fall uponan electrical drop modus operandi per-mits the conditions of theexperiment to be con-trolled and the results ac-curately recorded. It canin this way be shown thateven a very minute doseof the pituitary autacoid— whether the same hor-mone as that which affectsthe muscular tissue of theblood-vessels and viscera,cannot certainly be said —will cause milk which hasaccumulated in the glandto be immediately pouredout (fig. 64), whilst asomewhat larger dose willpr
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