FOODS HUMAN NUTRITION. 659 



III sonic of tlio tests tlio hc-uls with tlH> food niatorial attached were hiclosed 

 ill fjauze so that the food sui)staiiccs could not come in direct contact with the 

 walls of the dijjestive tract. In tests designed to study the «>ffects of gastric 

 digestion heads were attached to a silk thread and were withdrawn from the 

 stomach after a suitahle interval. 



Experiments with healthy iiersons showed, acconling to the author, that 

 hoth catgut and fish hones were digested in the stomach, whereas boiled or 

 raw meat (heef), r.iw chicUen skin, and both raw and boiled ])Otatoes do 

 not dissolve altogether in (his organ. Fish hone was selected for these experi- 

 ments as its solution in the digestive tract is positive indication of the pres- 

 ence of gastric juice. Catgut was used for the same purpose hut is not as 

 satisfactory. 



In the case of meat a swelling ;uid lessening of tlie fibers was noted in the 

 stomach. Raw muscle fiber and chicken skin disa])])eared in the intestines. 

 Tendons, however, remained undigested. Raw potatoes varied, sometimes 

 digesting entirely and sometimes ji.-issing through the body unchanged. Boiled 

 potato, generally si)caking. was ajjparently digested in the liowel, while the 

 skin of potato, either raw or boiled, was always excreted unchanged. Wax, 

 parafiin, and fats with a high melting point, such as stearic ncid, etc., were 

 not absorbed in the intestine, bat suet and mutton fat, which melt at 50° C, 

 were digested in the bowel. Other experiments made with mutton fat showed 

 that it remained unchanged in the stomach. 



To determine whether the disappearance of mutton fat in the intestines 

 was a chenii<-al or mechanical jirocess produced by the epithelium of the intes- 

 tine, beads containing mutton fat and surrounded by gauze were swallowed. 

 All the mutton fat in the beads disappeared which, according to the author, 

 shows that ch(4nical processes play the principal part in the absorption of 

 mutton fat. Thymus gland and potato were taken in a similar w'ay and it 

 appeared that the gauze envelope did not hinder digestion. 



The results obtained with normal subjects, in the author's opinion, show that 

 the method can be employed for testing digestion in disease and a number of 

 experiments made under pathological conditions are rejiorted. 



The acceleration of the action of the pancreatic juice by the salts of cal- 

 cium, E. Delezexne (lirit. Med. Jour., WDG, Ao. 2S99, pp. 1185, i7S6).— As 

 pointed out by the author in a paper presented at the Toronto meeting of the 

 r.ritish Medical Association, the iiancreatic juice obtained in its inactive form 

 from the pancreatic duct either by means of a permanent fistula or by the aid 

 of intravenous injections of secretin ac(iuires a very jiowerful proteolytic ac- 

 tivity when mixed with a suitable ([uantity of a solulile calcium salt and incu- 

 bated for several hours. 



"The action of the salts of lime must be considered a specific one. The salts 

 of other metals of the same series (barium, strontium, magnesium) have little 

 or no effect. Any slow action they may appear to possess may be explained by 

 the i)resence in them, or in the pancreatic juice itself, of traces of soluble cal- 

 cium salts." 



Chemical processes in the animal body, li. O. Herzog ( Chemisches Geschehen 

 ini Onjuniniintn. Hcidclhcru: Curl Riissler, lHO.j, pp. (52). — The possibilities are 

 discussed of applying to the inijiortant ferment reactions of the living body 

 the theories of chemical eciuilibrium and velocity of i-eaction. Although the 

 results as yet obtained are not altogether satisfactory, the author believes that 

 a mathematical treatment of the problem is possible. In a sjiecial case, dog 

 jjcpsin, a formula is i)roiK)se<l for the rate of secretion of (he enzym. 



