164 Kansas Academy of Science. 



(b) It may be used up in the oxidation of salts of these 

 metals. 



(c) It may combine with nascent hydrogen. 



(d) It may combine with fatty materials during processing. 

 A. W. Bitting, in "Methods Followed in the Commercial 



Canning of Foods,"" states : "It is always possible to tell a 

 'swell' from a 'springer' by the use of a microscope, as in the 

 former there will be large numbers of organisms, while in the 

 latter there will be very few." It will be inferred from this 

 statement that cans which are "bulged" only as a result of the 

 presence of hydrogen formed by the action of acids on tin are 

 to be considered as "springers." 



W. D. Bigelow, in the September, 1916, Journal of Industrial 

 and Engineering Chemistry, points out that tin in canned food 

 is largely, sometimes chiefly, in the form of insoluble com- 

 pounds ; that the acid acts as a carrier of tin from the coat- 

 ing of the container* to the food material. 



In the November Journal the same author states that with 

 nonacid foods such as peas or corn, swells are usually due to 

 decomposition. On the other hand, spoilage rarely occurs 

 with acid fruits unless the can be leaky. In this class of prod- 

 ucts swelling of the can is almost invariably due to hydrogen 

 set free by the action of the fruit acid on the metal of the con- 

 tainer. 



This review of the literature on the subject shows that no 

 work has been done on "springers" and "swells" involving the 

 quantitative determination of tin and the various gases. It 

 seemed desirable, therefore, to secure some data of this nature. 



If the hydrogen present in canned foods is the product ex- 

 clusively of the action of acids on the tin of the container, then 

 obviously there should be a definite relation between the 

 amounts of tin and hydrogen present. If the hydrogen is 

 partially the product of the action of acid on other metals of 

 the container, such as iron, then the hydrogen present should 

 be greater in quantity than that capable of being liberated by 

 the tin present. To obtain information in regard to this mat- 

 ter, determinations were made for tin and the various gases 

 in eighty-three samples of bulged canned goods. These rep- 

 resent the following products : corn, pumpkin, sweet pota- 



7. U. S. Dept. .\gri., Bui. 196, 1915. 



