39 



large proportion of tlu' continued infertilities after operation." 

 Is it possible for a bull to be infertile to the cows in his herd 

 that have been fed a deficient diet, and at the same time to breed 

 well when mated to animals outside this herd ? This is rather im- 

 probable in practice, but there is always the possibility of its 

 oceurrenee. In tlie experimental work, white rats were used: one 

 strain from tlie \Vistar Institute with a fertility of about 65 per 

 cent, and the other from a Dr. Castle's strain with a fertility of 

 about 90 per cent. The "Wistar rats were fed in groups, each 

 group receiving a diet deficient in a certain sul)stance : calcium, 

 protein, or fat soluble vitamine. To this grou]) was added a diet 

 deficient in both calcium and protein (war diet). These diets 

 reduced the fertility of the groups from the original 65 per cent, 

 to 55, ?)1. and 14 per cent respectively. It delayed the appearance 

 of fertilitv in voung rats raised on these diets, and lowered its 

 degree in the mature animals. Most of these rats, however, though 

 infertile to each other, bred promptly Avhen mated to the Castle 

 rats of known fertility. This demonstrates clearly that relative 

 infertility of given matings does occur. One interesting feature 

 of the work is the fact that in the matings on the single deficiency 

 diets, four deliveries of macerated fetuses occurred and there were 

 two more in eight deliveries from those reared on the war diet. 

 Xo cases of this kind had previously occurred in this strain, which 

 had 1)ecn under observation for several years. Does this throw 

 any light upon the cause of macerated fetuses in cattle? Micro- 

 sco]iically the testes and ovaries of these infertile rats showed no 

 observable changes, a fact which is of great importance to bear in 

 mind. 



Williams, in his book on disease of the genital organs, brings out 

 quite clearly the relation of defective diet, overfeeding, and lack 

 of exercise, to reproductive efficiency. 



Xovarro (40) observed that pigeons fed on a diet without vita- 

 mine B showed degeneration of the seminal epithelium, with 

 hypertrophy and hyperplasia of the interstitial cells of the testis. 

 Another author (Allen) .showed that reduction in the quantity of 

 water-soluble vitamine in the diet of rats resulted in total degenera- 

 tion of all the germ cells, but it did not interfere witli gi'owth and 

 development in other respects. 



The observations of Williams (41), in a pure bred beef herd in 

 Hawaii, clearly demonstrate the intimate correlation between poor 

 fodder as the result of extreme drought, and the accentuation of. 

 or increased susceptibility to, genital infections, as demonstrated 

 by clinical findings. The genital disorders started soon after the 

 onset of the drought, and immediately took a downward trend 

 with the advent of the rainy season. 



Judging by the work quoted, we will observe tliat deficient diet, 

 though it does not always affect the general health, has a ]irofnund 

 effect upon the genital organs of l)oth sexes, associated with dis- 

 turbances of spermatogenesis in the male. In most debilitated and 



