266 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XVI, 



fleas on the guinea-pigs ; to my surprise they were covered with fleas. 

 An examination of these fleas showed that they were rat fleas, Pulex che- 

 opis. The following history of the disease was given to me by the 

 Superintendent. A few days before the guinea-pigs became ill, dead 

 rats had been found near their cage. The guinea-pigs had then sickened, 

 and two keepers who had charge of them took plague and were seut to 

 hospital. One or two of the guinea-pigs had died before the dead 

 animals were sent to me for examination. When I saw the guinea-pigs 

 in the gardens many were sick, but some appeared healthy. It was. 

 interesting to note that the sickly were those most infested with fleas. 

 From one sick guinea-pig no less than eighteen fleas were removed. 

 This is an important fact to note, in that, thereby the number of in- 

 fected fleas will be greatly increased. An examination of a large 

 number of guinea-pigs kept in our Laboratory stock showed that these 

 animals seldom harbour fleas, the only flea found on them under normal 

 conditions is a very occasional Pulex fells. This unusual infection of 

 the guinea-pig by Pulex cheopis remained for some time a mystery; 

 but an explanation was gradually forthcoming. Here, no doubt, in- 

 fected rat fleas had communicated the disease to the guinea-pigs ; but 

 why were rat fleas found on guinea-pigs ? The problem was solved in 

 the following way. A friend who lived in two semi-detached bungalows 

 kept a cat. One of the bungalows was used as a nursery for the chil- 

 dren, and the nursery was the favourite haunt of the cat. When the 

 hot weather came on, the children were sent to the hills, the nursery 

 was shut up, and the cat had to find other quarters. About a month 

 later my friend had to re-open and enter the nursery to get some things 

 for the children. No sooner had he entered than he was bitten by a 

 flea, and then by another and another, and to his surprise he found 

 many fleas on his legs. He caught these fleas and brought them to me, 

 and when I examined them I found them to be cat fleas. Now as Ions 

 as the cat lived in the nursery, fleas never troubled the inmates, but 

 when the cat had been excluded the cat fleas swarmed on to man. 

 Starvation apparently had driven them to man. 



Another opportunity presented itself in the case of a stable. This 

 stable had been shut up for some weeks, but had formerly been inhabited 

 by a dog as well as a horse. When the door of the stable was opened, 

 fleas literally swarmed out on to the man who opened it, almost as a 

 hive of bees might do when disturbed. One had only to approach the 



