1156 EXPKHIMENT STATION RECORD. 



iiu'jit foods; the npplo anil ]tlimi imddin^is and a sanii»lo of apricot jam con- 

 tained al»ont ;> grains of (in to tlic ponnd. No saniitlcs of tlic caiuicd frnits 

 most connnonly consnmcd in this conntry (poars. apricots, pineapple, etc.) were 

 inclnded ... [in tlie samjdes e.\amined.| It was satisfactory to tind that th(? 

 liiflhest amonnt of tin present in samples of canned i)ears, apricots, and i)eaches, 

 obtained from a London im]iorter, who specially selected them as old stock and 

 stated them to be between 1 and 2 years old, was not more than 1.0;j gr. iier 

 ponnd." 



As the author notes, his investigations brought out a fact which he had ob- 

 served before witli meat extracts, namely, "that the tin after solution in the 

 liquid contents of tlie can, becomes in course of time absorbed in or chemically 

 combined with the solid contents (meat, fruit, etc.) in such a way that the 

 latter contain relatively larger quantities than the liquid itself. 



" Other examinations tended to emphasize the important part which may be 

 played by unsatisfactory soldering in connection with high degrees of contami- 

 nation ; . . . It is evident that the presence of solder in the contents of the 

 can may cause ver.v pronounced solution of tin ; no doubt owing to electrolytic 

 action. It is possible that unsatisfactory tin plate (e. g., cans which have i)een 

 so thinly coated on the interior that the underlying metal is at points prac- 

 tically exposed to the action of the contained liquid) may also tend to affect 

 the extent of solution of tin by means of electrolytic action." 



In pharmacological studies of which the author himself was the subject tin 

 in the form of a double tartrate with sodium was taken during three weeks. 

 Urine and feces were collected and examined. 



"In the one experiment on a human being, the excretion of tin kept pace for 

 a fortnight with the intake, when the latter did not exceed 2 gr. daily. With 

 an increase of dose in the third weelv, there was some evidence of a cumulative 

 action. , . . There was in all cases relatively small amount of absorption from 

 the alimentary tract, as indicated by the small amounts of metal excreted in 

 the urine. When tin enters the system by a channel other than the alimentary 

 tract, the metal is excreted (at any rate in the case of dogs) in larger quantities 

 in the urine than in the feces. . . . 



The data i)resented ..." do not indicate much probaliility of serious risk of 

 chronic poisoning by the absorption of nonirritant compounds of tin as a result 

 of a diet which consists largely of canned foods and is continued over consider- 

 able periods of time." 



The work of other investigators is summarized and discussed in connection 

 with the experimental data reported and a l>ibliography is appended to the 

 pai)er. 



The deterioration and commercial preservation of flesh foods. I, General 

 introduction and experiments on frozen beef, W. I). Richardson and E. Scni:- 

 RUBEL {Join: Atiicr. CIiciu. .Soc. 30 (IHOS), ^o. 10, mi. lolo-l.jfi',). — The general 

 subject of deterioration of meat is di.scnssed and results of experiments reported 

 on the physical and cliemical changes which take i)lace when meat is kept in 

 cold storage. 



The physical changes in frozen beef may be due to desiccation or to pressure 

 jtrodnced by the expansion of water during the freezing process and particularly 

 to the fact that water freezes outside the cell walls. Another jthysical effect in 

 meat under conditioms of storage lies in the contraction of the insolul)le tissue 

 elements which takes place even when the moisture remains constant. The 

 temperature at which meat becomes solid depends upon phenomena connected 

 with the lowering of the freezing point of water by the presence of soluble 

 solids and similar constituents. 



The evidence from l>oth cultural and microscopic examinations of frozen beef 

 led to the conclusion that bacteria are not capable of penetrating it in this con- 



