OCTOBEE 11, 1907] 



SCIENCE 



475 



various acids, alkalies and salts upon com- 

 plements renders the complement-deviation 

 phenomenon for forensic purposes less safe, 

 heeause the materials are often impure in 

 practical cases. 



Various soluble salts of oleic acid are ac- 

 celerators of the complementary action of 

 serum. 



A Study of the Influence of Lecithin on 



Growth: A. J. Goldfaeb. 



The author's experiments included three 

 series of over 1,200 tadpoles. In each series 

 the lecithin varied in strength from 1/150 per 

 cent, to 2 per cent, (the toxic concentration). 

 In one series (1) the tadpoles were not fed, 

 in another (2) they were given minced worm, 

 in the third (3) they were given a liberal 

 supply of plant debris. 



The tadpoles that were kept in lecithin 

 solutions did not show any greater increment 

 in weight or size than the controls of the same 

 series. There was a marked difference, how- 

 ever, in both the size and weight of tadpoles 

 of one series compared with the tadpoles in 

 the corresponding solution of another series, 

 due to the kind (and presumably the amount) 

 of food given. Individuals of series 1 were 

 smallest and weighed least; those of series 3 

 weighed from 3 to 6 times as much and were 

 twice as broad as the tadpoles in the same 

 strength of solution in series 2. 



Toung kittens (over 50 in number) were 

 treated as follows : 



Series 1. Lecithin was injected subcuta- 

 neously daily in doses of from 0.0006 to 0.004 

 gram. Control animals received subcuta- 

 neously equal volumes of physiological salt 

 solution. The increase in weight was some- 

 what greater in the kittens that received the 

 lecithin. 



Series B. Lecithin was injected subcuta- 

 neously in doses of from 0.01 to 0.32 gram 

 daily. The kittens that received the lecithin 

 gained, in some cases, as much as 7 per cent, 

 over the control animals. 



Series 3- Lecithin was fed daily in 

 amounts of from 0.01 to 0.32 gram. With 

 very few exceptions, these kittens weighed 



from 2 per cent, to 12 per cent, more than 

 the controls. 



The best results were obtained in the feed" 

 ing experiments, with doses of from 0.04 to 

 0.16 gram daily; yet under these conditions, 

 the actual difference in weight between the 

 kittens fed with lecithin and those not so 

 fed was small, amounting on an average to 

 about 7 per cent. Whether the same quantity 

 of any other fatty or simple nutrient com- 

 pound would result in an equal increment has 

 not yet been determined, but will be investi- 

 gated with other matters bearing upon the in- 

 terpretation of the results recorded above. 



Comparative Data for the Elementary Com- 

 position and the Heat of Combustion of 

 Collagen and Gelatin: Charlotte E. Mann- 

 ing and William J. Gies. 

 Comparative elementary analyses, as well as 

 determinations of the heat of combustion, of 

 many samples of connective tissue collagen 

 and gelatin, have indicated that there is a 

 closer agreement between the mother sub- 

 stance and its derivative, on these two planes 

 of comparison, than the prevalent idea of their 

 chemical relationship would indicate. The 

 following sample data show this quite clearly: 



The differences between the above figures 

 for nitrogen and hydrogen contents harmonize 

 with the observation by Emmett and Gies 

 that nitrogen is eliminated as ammonia when 

 collagen is converted into gelatin by treatment 

 with hot water, and also strengthen their con- 

 clusion thafgelatin is not a simple hydrate of 

 collagen. 



On the Fate of Elastose after its Sub- 

 cutaneous or Intraperitoneal Injection: a 

 Preliminary Inquiry into the Origin and 



'Each of these products was desiccated (before 

 analysis) to constant weight by the Benedict- 

 Manning process in vacuo. See the American 

 Journal of Physiology, 1905, XIII., p. 309. 



