Some of the blood conditions of starvation may be produced temporarily by excessive hemorrhage. It is recognized, of course, that hemorrhage also introduces factors not present, at least in moderate starvation, such as the temporary diminution of hemoglobin. Nevertheless, the results of two series of experiments with the effects of excessive hemorrhage are so striking and conclusive that they are reported, even though we have not worked out their interpretation. The results are most conveniently stated by the following brief protocols:

Dog I. Weight 6.0 kg.

Oct. 20. Types II and III gastric hunger contractions.

" 21. Type 1 contractions. Gastric tonus=3 cm. chloroform.

41 22. u I u =3 cm.

u 23. u I u u =3 cm.

u 24. u I " u =2Jcm.

"27. 9:12 a.m., light ether anesthesia; 146 c.c. blood drawn from carotid artery at 9:30 a.m. Recording of the gastric hunger contractions began 10:08 a.m. At this time the stomach was atonic and quiescent. A gradual return of gastric tonus appeared at 10:30 a.m. At 11:00 a.m. the gastric tonus was 5 cm. chloroform with vigorous type III hunger contractions, and this condition persisted till the end of the experiment at 12:30 p.m.

Oct. 28. Type I contractions. Gastric tonus =2§ cm. chloroform.

" 29. " I u " u =3 cm.

u 30. * I u u u =3 cm.

u 31. a I " =2} cm. . a

Control Experiment on Dog I

November 18, Ether Anesthesia for 20 Minutes

Nov. 18. Type I contractions (very feeble). Gastric tonus 2 cm. chloroform. "19. "I contractions (feeble). Gastric tonus 2 cm. chloroform. a 21. " I " a 3 cm.

"25. "I u u 2 cm.

8 26. " II " " 3lcm.

Dog II. Weight 6.7 kg.

Oct. 30. Type I hunger contractions. Gastric tonus 2 cm. chloroform.

" 31. u I u u a u 2 cm. "

Nov. 3. u I and II hunger contractions. Gastric tonus 3 cm. chloroform.

" 4. a I hunger contractions. " "2 cm. "

" 5. a I u u u 2 cm. " u 6. 9:10 a.m., 169 c.c. blood withdrawn from carotid artery under light ether anesthesia. Record of gastric contractions began at 9:45 a.m. At this time the stomach was quiescent with feeble tonus. At 10:00 a.m. the gastric tonus began to increase. At 10:30 a.m. the gastric tonus was 9 cm. chloroform with type III vigorous hunger contractions. This condition persisted till the end of the experiment at 11:30 a.m.

Nov. 7. Types II and III contractions. Gastric tonus 2 J to 3 cm. chloroform. u 11. u Ilandlll u u u 3 to 7 cm.

" 12. Type I " u 2} cm.

Control Experiment on Dog II

November 18, Ether Anesthesia for 20 Minutes

Nov. 18. Types I and III contractions. Gastric tonus 1 to 4 cm. chloroform. u 20. * I and III u u 2 cm.

" 21. Type I " tt 2 cm.

a 24. u I u a 2 cm.

u 25. u III " " 3 to 4 cm.

u 26. Types I and III * a " 3 to 6 cm.

The reader will note that in both dogs the hemorrhage induced temporarily a greater gastric tonus and intensity of hunger contractions than those typical for these dogs before the hemorrhage. This effect of the hemorrhage disappears in less than 24 hours. The controls show that the stimulation of the gastric tonus mechanism is due to the hemorrhage, and is not an after-effect of the ether anesthesia. That they were felt as hunger contractions by the dogs was evidenced by the amount of food consumed on the hemorrhage days.

Fig. 28.-A, tracing showing gastric tonus and type I hunger contractions characteristic of dog before hemorrhage. B. record of gastric tonus contractions of dog 60 minutes after drawing i6g c.c. blood from the carotid artery; showing the temporary stimulation of the gastric hunger mechanism as an after-effect of excessive hemorrhage (bottom of tracing = o mm. pressure) (Luckhardt).

The following considerations might be offered, not only as a possible, but also as a probable explanation. The blood is, of course, the purveyor of nutritive substances to all the tissues of the body. Its chemical composition is kept remarkably constant. If now an animal is bled extensively (2 to 3 per cent of body weight), there is removed suddenly an enormous amount of pabulum, that is, of those various substances which are taken up by the different tissues during circulation. The organs and tissues deprived of these respective nutritive substances become hungry (call for food) by giving up a something (a hormone) which acts on the neuromuscular apparatus of the stomach to produce the hunger contractions.

We recognize, of course, that acute hemorrhage introduces other factors. Some of them have been mentioned. The explanation offered gives a simple, reasonable picture of the mechanism involved. By acute hemorrhage we induce sudden acute starvation. Probably all the tissues of the body give up this " hunger hormone." By withholding food from the animal the blood changes appear more slowly, depending for one thing on the state of nutrition and reserve food supply of the animal before the period of starvation is started.