Chapter 231 The Fat and White Thing
Of course, Lu Chuan only gave a rough explanation.
The specific operation is much more detailed.
The idea that you can tell the time of death by judging the length of a maggot at a glance is mostly written in the script.
In fact, in forensic entomology, judging the time of death of a corpse through the growth cycle of corpse parasites requires many experiments to assist.
Wang Changjiang was a little confused after hearing Lu Chuan's explanation.
With his knowledge base as a professional forensic doctor, he can certainly understand what Lu Chuan is talking about.
But just because I can understand it, I am confused.
Isn’t Lu Chuan a current detective?
When did forensic entomology, a relatively unknown profession even among forensic medicine, still have an understanding of it?
He understands skeletal identification and analysis, and now he seems to have some understanding of forensic entomology.
What did this guy study when he went to college?
Behind the gas mask, Shen Yan's expression was very calm.
Lu Chuan once told her that he had some knowledge of forensic entomology.
Although Liu Guodong didn't know that Lu Chuan also had some research on forensic entomology.
But in terms of current investigation, fingerprint identification analysis, skeleton identification analysis, etc., Lu Chuan has shown enough.
Now that there is one more item, nothing seems impossible.
Ahem.
Liu Guodong coughed lightly: "That's it. I'll go back and do the experiment first. The identification and testing of the sharp knives from Yang Sen and Lao Bai haven't come out yet. I'll go over and take a look."
"Little Lu, there’s nothing big going on over there. You can help Forensic Doctor Wang determine the time of death of the body.”
Liu Guodong took the clothes and left.
“What needs to be done next?”
As the chief forensic surgeon responsible for the anatomy, Shen Yan first sought Lu Chuan’s opinion before performing the surgery herself.
"I need to collect a sufficient amount of larvae here, as well as some skin and internal organs fragments on the surface of the corpse."
"It is best to collect the liver and eyelids, if possible. If you can extract it, it’s best to have some.”
Any insect eggs that parasitize on corpses are overwhelmingly corpse flies.
The larvae of these corpse flies, just after hatching, have no teeth and no other means of attack.
So corpse flies will choose the softest place to lay their eggs.
On the surface of the corpse, the first places where parasite eggs are found are the eyelids, nasal mucosa, oral mucosa and other parts.
Inside the corpse, the liver is the fattest and most tender, and it is also the first to be parasitized and later putrefied.
Shen Yan nodded. Lu Chuan was obviously not good at these specific operations, and she, a professional forensic doctor, needed to do them.
The two of them were working and chatting.
“I learned when I was in college that corpse fly eggs begin to hatch after two or three days of parasitism, right?”
Although Shen Yan has not done much research on forensic entomology , but the basic knowledge reserve is there, not only there, but also sufficient.
Lu Chuan nodded in affirmation: "In most cases, this is the case, but the most important thing is to look at the outside temperature and humidity."
"The incubation of corpse fly eggs will not begin until the temperature is above 15 degrees Celsius, and the maximum hatching temperature cannot exceed 40 degrees Celsius."
"If the weather is cold, the incubation period can be delayed by about a month at most."< br>
“If the outside temperature is around 35 degrees Celsius, this cycle will be shortened to one day. Even if the humidity is also relatively suitable, the incubation time can be shortened to about twelve hours at the shortest.” Lu Chuan will A white and fat larvae of different sizes was put into the bottle. I lifted it up and looked at it. Each one was abnormally fat and squirming crazily at the bottom of the bottle.
Obviously, judging from the size of the larvae, the hatching times of these eggs are not synchronized.
Shen Yan nodded. She could not remember these things clearly. Maybe she had learned them but forgotten them, or maybe she had never learned them at all.
"I remember it was said in the book that the emergence period of a general corpse fly is about a week?"
"Yes," Lu Chuan continued to put the larvae that Shen Yan had stripped off the corpse into the bottle: "But the time of death of the corpse cannot be determined based on this."
Because what Lu Chuan needs to do now is to find the largest and smallest among them, and determine their intergenerational relationship.
“The largest larvae on the corpses are not necessarily the offspring of the first batch of flies that laid eggs.”
"It is very likely that it is the second generation, or even the third generation."
If it is confirmed to be the first generation, then the body should have decomposed in about a week.
This also depends on the external environment where the body is located, but it will most likely not exceed two weeks.
But the weather in Haizhou City in April has recently become warmer, but it is not very hot.
At least it has not yet reached the optimal incubation temperature for corpse fly eggs.
Bodies will not decay quickly in this environment.
But considering the degree of decay of the corpse, it doesn't look like it could become like this in a week or two.
So, corpse fly eggs may not be the first generation, but may be the second or even third generation.
“The possibility of the fourth generation is very small. If the corpse fly has developed to the fourth generation, then the eggs will take at least one month to hatch.”
Lu Chuan provoked A very small larvae, only about three millimeters: "The weather in Haizhou City is relatively cold in three months, the decay of corpses will not be so serious, and the corpse flies that breed will not be transmitted from generation to generation so quickly."
The two of them were chatting, and Wang Changjiang listened quietly from the side without interrupting. He was probably more interested in the content of their chat.
But as the most experienced forensic doctor in Haizhou City, I always feel a little embarrassed to ask a newly hired detective on forensic issues, or to learn secretly.
So, Wang Changjiang simply stopped talking. Anyway, his task today was to record.
Shen Yan came from a major and has been working for more than two years. She has rich work experience and theoretical knowledge.
Dissecting a corpse is easy.
"Actually, maggot larvae are not all harmful. I read a document last year that talked about using fruit fly larvae to suck carrion to accelerate the rapid healing of decaying wounds."
The selection of larvae on the surface of corpses has almost ended , Shen Yan was about to go under the knife and start the dissection.
“There is such a treatment method, but it is used more clinically abroad. In China, well, it is still used less.”
“The main reason is that there is a lack of knowledge in this aspect. Talent.”
Creating fruit fly larvae is not a particularly complicated matter.
The key is how to perform sterile culture.
Otherwise, if you use fruit fly larvae that breed from random carrion to treat decayed wounds, it is estimated that new infections will come before the old wounds heal.
But in a sterile environment, corruption will stop, and fruit fly larvae will naturally not be able to hatch and grow.
This seems to be a fundamentally paradoxical subject.
But Lu Chuan knew that it was possible to cultivate in a sterile environment. He had this knowledge in the intermediate-level corpse parasite egg identification analysis he accepted.
(End of this chapter)