---------+--------+----------+-----------+----------------------------
| | |Treatment |
Date. | Weight.| Food. |(2 per cent| Symptoms.
| | | caffein). |
---------+--------+----------+-----------+----------------------------
|_Grams._| _Milk_ | _cc._ |
| | _(cc)._ | |
Apr. 28 | | 300 | |
Apr. 29 | 1,280 | 300 | |
Apr. 30 | 1,290 | 300 | |
May 1 | 1,315 | 300 | |
May 2 | 1,330 | 300 | |
May 3 | | 300 | |
May 4 | 1,360 | 300 | |
May 5 | 1,365 | 300 | |
| |_Meat_ | |
| |_(grams)._| |
| | | |
May 6 | 1,395 | 60 | |
May 7 | 1,365 | 80 | |
May 8 | 1,340 | 180 | |
May 9 | 1,380 | 180 | |
May 10 | 1,400 | 180 | |
May 11 | 1,425 | 180 | 14.5 |No symptoms.
May 12 | 1,470 | 180 | None. |
May 13 | 1,485 | 180 | None. |
May 14 | 1,510 | 115 | 14.5 | Do.
May 15 | 1,500 | 115 | 14.5 | Do.
May 16 | 1,485 | 115 | 14.5 |Passed worms.
May 17 | 1,480 | 115 | 14.5 |
May 18 | 1,485 | 115 | 19.5 |Feces soft and black;
| | | | almost diarrhea.
May 19 | 1,495 | 115 | 19.5 |
May 20 | 1,500 | 115 | 19.5 |Scratches her eyes and
| | | | chases her tail.
May 21 | 1,500 | 115 | 17.0 |
May 22 | | 115 | 17.0 |
May 23 | 1,470 | 115 | 17.0 |
May 24 | 1,465 | 115 | 20.0 |
May 25 | 1,450 | 115 | 20.0 |Feces soft and black.
May 26 | 1,450 | 115 | 23.0 |Diarrhea and worms.
May 27 | 1,355 | 115 | 23.0 |Refused to eat all food.
May 28 | 1,270 | 115 | 23.0 |Threw up worms, stiff, and
| | | | has skin over both eyes.
May 29 | | | |Found dead.
---------+--------+----------+-----------+----------------------------
Highest amount of caffein given, 362 mg per kilo. No autopsy.
Examination of the results obtained in the experiments of series C
shows that young and growing dogs tolerate large amounts of caffein.
In four subjects of this series, Nos. 1, 2, 3, and 6, no effect was
observed when moderately large amounts (160 to 200 mg per kilo of
caffein) were fed. Symptoms were noticed only when these amounts of
caffein were increased from 50 to 60 per cent. The other two dogs,
Nos. 4 and 5, of this series were less resistant, however, to caffein,
as 0.16 gram of the drug per kilo induced well-marked symptoms.
Since these were fed meat, while Nos. 1, 2, and 3 received milk, the
difference in toxicity may be due to the diet employed, but No. 6,
which likewise received a meat diet, failed to show the effects of
caffein when 200 mg per kilo were fed. On the other hand, it should
be noticed that No. 1 died after receiving 360 mg per kilo, No. 2
survived a dose of 334 mg, while No. 3 died after a dose of 322 mg
per kilo of caffein. The fatal doses for Nos. 4, 5, and 6 were 287,
335, and 300 mg per kilo, respectively. Although the differences are
too small to justify any definite conclusion regarding the effect of
a milk diet or of a meat diet on the toxicity of caffein, the results
nevertheless suggest a reasonable possibility that caffein is more
toxic to young dogs when on an exclusively meat diet than when fed
milk. It is perfectly evident, however, that the resistance to caffein
in either case is very great, almost twice that of adult subjects.
As shown in series A and B, 125 to 175 mg per kilo proved fatal to
all but two animals in these experiments, while symptoms of toxicity
appeared after much smaller doses. In other respects the behavior of
young dogs toward caffein was the same as that of the adult. In neither
case was cumulation nor tolerance observed under the conditions of
these experiments. The findings at autopsy were likewise similar,
as gastro-enteritis was the chief lesion observed on macroscopic
examination. It might be mentioned, however, in this connection, that
the symptoms of caffein intoxication in young dogs often presented
marked differences from those observed in those of more advanced age.
The resemblance of the effects of caffein in young puppies and in
rabbits was very striking. In both, the tonic with clonic convulsions
were observed after a sufficient quantity of caffein was administered.
In the dogs which were fully grown a large dose of caffein was usually
followed by tonic convulsions and almost instantaneous death.
Moderately large amounts of caffein fed daily to puppies for several
days--in some cases as long as 10 days--induced mild symptoms only. No
cumulative effect was observed in any of the experiments of series C.
There seems to be tolerance of certain functions toward caffein, but no
general tolerance of the body could be obtained in these experiments.
Caffein is apparently less toxic for adult dogs on high than on low
protein diet. In young and growing dogs caffein is somewhat less
toxic when milk, rather than meat, forms the exclusive diet. Some
pathological conditions apparently increase the toxicity of caffein
also in dogs. The symptoms of caffein intoxication observed in young
dogs are in some respects different from those in full grown and older
animals, and resemble those noticed in rabbits.