THE VITAMINES IN THE ANIMAL KINGDOM 99 



the animals forcibly fed, a greater proportion develop the typical 

 beriberi symptoms, after a period of time which is subject to great 

 deviations. We may say, however, that most of the animals develop 

 the disease in from 10 to 30 days; it is noticeable that the animals 

 mostly become sick within a few days of each other, so that there is 

 the false impression of the appearance of an epidemic. In the 

 individual animals, we note the development of various types of 

 diseases, as illustrated in the accompanying pictures, closely resem- 

 bling the conditions described in man. This analogy may well be 

 fallacious and the types described below may depend perhaps only 

 on the nutritive condition and the length of time the rice is fed. 



In one type, which we shall designate as acute, we notice that the 

 ability to walk is decreased. If the animal is frightened, it runs a 

 few steps without difficulty, but when fatigue sets in, the animal 

 helps itself by flapping its wings, but sits motionless when left alone; 

 the heart beat is pronounced and behaves as though it had been over- 

 exerted. The next symptom is uncontrolled motions of the head. 

 If the animal is turned about several times in the air, then in many 

 cases the acute form is produced out of the latent. The phenomenon 

 appears quite suddenly the head is pressed against the back by a 

 retraction of the neck muscle, the legs are drawn up to the belly; 

 the animal turns somersaults, and this may last a long time under 

 certain conditions. In this stage, the animal does not survive very 

 long. During the course of a day, a disturbance in breathing 

 develops; the animal opens its beak wide, apparently struggling 

 against suffocation, and finally death results in from 12 to 24 hours 

 after the appearance of the symptoms, with an easing up of the 

 spasms. 



The second or chronic type (figs. 14-15) develops as follows: 

 After a few weeks the animal is found sitting in the cage; it moves 

 very reluctantly in spite of its ability to do so. After some days, 

 it loses even this capability, and sits motionless in one spot. Only 

 seldom does this form go over into the spastic. Usually, the animal 

 lives a few weeks longer and dies without moving from its place. 

 These cases are not suitable for curative experiments. For this 

 purpose, we must use only those animals in the first group. 



The latter also show variations. In some, the spastic condition 

 persists till death while in others, it disappears for short intervals 

 only to reappeaT in a more severe form. 



