(b) NaCl + CaCl2. The phenomena described above as occurring when isolated loops of intestine are immersed in mixtures of LiCl and CaCl2 can be produced also in mixtures of NaCl and CaCl2. The behavior of loops placed in pure CaCl2 and in pure NaCl has been described. In the former the loop remains motionless; in the latter regular rhythmical movements continue for 40 minutes or more.
When, however, a loop is placed in 50 c.c. m/6 NaCl + 10 c.c. m/6 CaCl2 there are no movements whatever to be seen at first. The loops remains quiet for about 10 minutes. The movements which are seen from the beginning in the control loop in pure NaCl solution have apparently been inhibited by the CaCl2 present in the mixture. After 10 minutes, however, the loop gradually becomes very active, and violent contractions appear which are similar to those described as taking place in mixtures of LiCl and CaCl2. The loop becomes much more active than the control loop in pure NaCl. The onset in the LiCl mixture is more sudden, but otherwise the phenomenon is practically the same. The movements in NaCl + CaCl2 persist for 30 or 40 minutes, sometimes for an hour. When the concentration of the CaCl2 in the mixture is relatively great this effect is not obtained. This is shown in the following table:—
| Time. | 50 c.c. NaCl | 50 c.c. NaCl + 5 c.c. CaCl2 | 50 c.c. NaCl + 10 c.c. CaCl2 | 50 c.c. NaCl + 20 c.c. CaCl2 | 50 c.c. NaCl + 40 c.c. CaCl2 | 50 c.c. CaCl2 |
|---|---|---|---|---|---|---|
| 10:35 | quite active | no movements | no movements | no movements | no movements | no movements |
| 10:40 | quite active | no movements | no movements | no movements | no movements | no movements |
| 10:45 | quite active | slight movements | slight movements | no movements | no movements | no movements |
| 10:50 | less active | slight movements | slight movements | no movements | no movements | no movements |
| 10:55 | still active | very active | very active | no movements | no movements | no movements |
| 11:00 | still active | extremely active | extremely active | no movements | no movements | no movements |
| 11:15 | still active | extremely active | extremely active | no movements | no movements | no movements |
| 11:30 | almost stopped | extremely active | extremely active | no movements | no movements | no movements |
| 11:45 | no movements | movements quieter | movements quieter | no movements | no movements | no movements |
| 11:50 | no movements | no movements | no movements | no movements | no movements | no movements |
Thus here also, as in the case of LiCl and CaCl2, there are produced effects in mixtures of NaCl and CaCl2 which cannot be brought about by either salt alone. The presence of CaCl2 seems to inhibit the movements which are first present in a loop placed in NaCl solution. When added in small quantities, e.g., not more than 10 c.c. m/6 CaCl2 to 50 c.c. m/6 NaCl, it produces after an interval of 10-15 minutes very violent movements such as are never seen in pure NaCl solution nor in pure CaCl2. When, however, it is added in greater proportion than this, e.g., 20 or more c.c. CaCl2 to 50 c.c. NaCl, all movements are stopped. The explanation of this is no more clear than the similar occurrence in mixtures of LiCl and CaCl2.
If a loop be placed in a mixture of LiCl and NaCl in equal parts, movements appear such as are seen in pure NaCl, but do not persist for so long a time. In the mixture of these two salts no such result is obtained as has been described in mixtures of LiCl and CaCl2 or of NaCl and CaCl2. Mixtures of CaCl2 and MgCl2 also produce no such movements. In these few salts it seems to be a mixture of chlorides of a monovalent with a bivalent metal which produces the extreme activity of the loop, while mixtures of chlorides of two monovalent metals or of two bivalent metals do not bring this about.
FOOTNOTES:
[61] MacCallum, J. B.: University of California Publications, Physiology, Vol. II, 1905, p. 47.
CHAPTER VIII.
The Effect on the Intestine of Intravenous Saline Infusions.
It has been frequently observed that a quantity of fluid enters the intestine during the intravenous injection of normal salt solution. According to Dastre and Loye,[62] the fluid injected into the veins is largely eliminated by the kidneys, although these organs may be assisted in this function by the salivary glands and intestine. These authors have found fluid to be present in the intestine of rabbits as well as in the pleural and peritoneal cavities after the injection of large quantities of salt solution. They state that in such an intravenous injection diarrhœa often results which may be so pronounced that a clear fluid emerges from the rectum. Knoll[63] also mentions the production of diarrhœa by the injection of large quantities of NaCl solution.
Magnus[64] in his work on the production of oedema of the skin by intravenous infusions of salt solutions shows in his tables that a certain amount of fluid is eliminated by the intestines after the kidneys have been removed. A rabbit with both kidneys removed was infused with 1,500 c.c. normal salt solution; 200 g. were eliminated by the intestine. In a second rabbit 1,010 c.c. of fluid were injected into the veins and 60 g. were eliminated by the intestine. In a dog 1,760 c.c. were injected and 160 g. eliminated by the intestine.