20 CAKEY P. McCOKD 



cat is small and unimportant. It should be noted that our extracts were in 

 all cases more concentrated than those employed by these investigators. 

 On the whole, our work would seem to indicate that while certain definite 

 effects on the circulation and secretion of urine are produced in certain 

 animals, as the result of intravenous injections of extracts of the pineal 

 body, the action is relatively slight when compared with that produced 

 by extracts from other glands known to furnish internal secretions. 



"Our experiments obviously deal with only a possible role of the pineal 

 body in producing certain relatively rapid effects on the circulation, 

 respiration, and secretion of urine. They leave entirely untouched the 

 possibility of more gradual effects over longer periods of time, as well as 

 the influence these bodies may exert on metabolism or other functions and 

 their relation to other organs of internal secretion." 



In Dana and Berkley's report (1913), which has been considered in 

 detail in the section on feeding experiments, reference is made to some 

 cardiovascular studies. The following is a quotation summarizing their 

 findings : 



"The blood pressure experiments were virtually negative. Two dogs 

 were used. The first dog received in rapid divided doses, intravenously, a 

 concentrated solution of the nucleoproteid extract of thirty calves' glands. 

 There was no response. The same animal then received intravenously 2 

 oz. of the globulin-albumin content of the same glands without results. 

 The second dog received a concentrated, filtered, saline solution of twenty- 

 four bullocks' pineals, with no essential response." 



With the idea that extracts of very young animals might be more 

 potent than those commonly employed, a series of observations was made 

 by Horrax with glands from calves and young sheep. The material 

 was obtained fresh from the abattoir, ground up in a mortar and dried in 

 the air. A part was mixed with lactose in the proportions of 1 :3, and 

 when used was weighed out as powder and dissolved or taken up in nor- 

 mal salt solution. Medium sized dogs were used and the injections were 

 made into the left external saphenous vein. 



Injections of small amounts (0.1 gm.) gave practically no result. 

 There was a variable, moderate fall in blood pressure, with no effect on 

 respiration or on the flow of cerebrospinal fluid. With larger amounts of 

 the powder (0.5 gm.) a constant fall in blood pressure was recorded, vary- 

 ing from 10 to 24 mm. of mercury. The immediate effect of the injec- 

 tion lasted on the average about two minutes, the pressure in all cases 

 showing a subsequent gradual rise to normal over a period varying from 

 ten to fifteen minutes; in no case was there a subsequent pressor response. 



In order to test the effect on the flow of cerebrospinal fluid, the Gush- 

 ing-Weed method of puncturing the third ventricle was employed, each 

 drop, as it fell from the cannula, being recorded by a marker on the drum. 

 The effect on the cerebrospinal fluid was that which might be expected 



