434 THE EXPERIMENTAL PRODUCTION OF AN INTERNAL HYDROCEPHALUS. 



from this organism affected many of the best litters. Again, the kittens with the 

 unwieldy heads were unusually apt to fall and receive injury to the head, etc. 

 Others finally reached a point apparently when the increasing cerebro-spinal pres- 

 sure affected the medullary centers. 



The protocol of a typical experiment with injection of a suspension of lamp- 

 black into the subarachnoid space of a kitten is given below : 



Litter of 4 kittens (N 3 ) born May 22, 1918. 



When 20 days old (June 12, 1918) the whole litter was in excellent physical condition. 

 Three of the litter were used for experimental injections and the fourth used as control. 

 The history of one of the experimental animals (No. 41) and the control will be given. 



The experimental kitten was on this day given ether and without shaving hair, punc- 

 ture through the occipito-atlantoid ligament was done with release of about 0.5 c.c. clear 

 cerebro-spinal fluid. Through this needle a subarachnoid injection of 1.0 c.c. Ringer's 

 solution containing a 10 per cent suspension of lampblack was made. At the time of injec- 

 tion the fontanelles of all of the litter were closed and the whole skull bony, as determined 

 by palpation. The litter was returned to mother. 



On the next day (June 13) the experimental kitten was in excellent condition and its 

 skull still tightly closed. The control was normal and active. 



The second morning, however, a difference could be made out between the kittens. 

 The experimental animal's cranial bones were definitely separated, but with a narrow 

 fibrous interval. The control remained as before. 



On the third day it was noted that the experimental kitten could not lift its head from 

 the ground, though apparently in excellent physical condition. The animal revolved about 

 its enlarged and heavy head as about a fixed point. The anterior fontanelle was extremely 

 widely opened and the longitudinal and transverse sutures about 3 mm. wide. 



This enlargement of the head continued, with the suture lines widening to 4 mm. and 

 the fontanelle becoming still larger. The convexity of the calvarium between the ears 

 increased and the forehead became high and prominent. On the fifth day it was noted 

 that the lower lid was being pulled up, covering the lower half of the pupil. The control 

 animal remained normal and active, its skull remaining bony and enlarging as that of any 

 normal animal. 



On the eighth day the following notation regarding the experimental kitten was made: 

 "Same excellent general condition. Head has become very large and forehead is extremely 

 prominent and high. Eyes are fast becoming obscured by the pulling-up of the lower lid; 

 the sclera constantly shows as a white crescent above. Fontanelles and sutures are becom- 

 ing larger each day, bulging and protruding somewhat. The kitten can just lift its head 

 up but a profound ataxia characterizes all movements. Can progress only by pushing its 

 head along the ground." On the same day the control was recorded as "Excellent shape. 

 Active. Fontanelles tightly closed; bony skull." 



The animal continued to gain in strength and was able to raise its head and move 

 around fairly readily though with considerable ataxia. On the twelfth day it was noted 

 that "from the glabella the forehead rises almost perpendicularly. The sutures are pal- 

 pable from glabella posteriorly to occiput; laterally they may be traced far down under 

 temples. All these suture-lines are from 6 to 8 mm. wide while the fontanelle has a diameter 

 of 10 mm." A photograph (fig. 11) of the animal on this day (June 24, 1918) is reproduced. 

 Again, the next day, "Bony edges of the former calvarium are very ill defined and small. 

 Whole head seems soft and fibrous. Orbital ridge almost obliterated." The control 

 remained normal. 



Unfortunately the animal developed a very acute bronchisepticus infection and was 

 sacrificed, with the normal control, on the fourteenth day (June 26, 1918). 



